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AnkiMCP is an Anki addon that implements an MCP server, enabling AI assistants to interact with the Anki flashcard application. Prior to version 0.21.0, `anki_mcp_server/mcp_server.py` globally disables FastMCP DNS-rebinding protection through `TransportSecuritySettings` with `enable_dns_rebinding_protection=False`, including for the default local Streamable HTTP listener. The defaults in `anki_mcp_server/config.py` enable `http_enabled` on `127.0.0.1:3141`, with an empty `http_path` selecting the root endpoint. No bearer token, API key, session secret, strict `Host` allowlist or strict `Origin` allowlist is enforced before `initialize`, `tools/list` and `tools/call` reach MCP dispatch. A victim who visits a malicious web page while Anki and the listener are running can have browser requests rebound to loopback, allowing the attacker to `initialize` MCP, enumerate tools, read the local collection, and perform enabled non-destructive note/deck creation or updates. The attacker needs neither LAN position nor a local process. Available operations depend on enabled tool filters; destructive tools are hidden unless `enabled_destructive_tools` is opted into, limiting deletion-level impact but not the exposed read/write operations. The reported harness confirms real MCP tool dispatch with substituted Anki bridge responses rather than demonstrating destructive changes to a real collection. Disabling protection for tunnels/proxies also disables it for the normal loopback configuration. This issue is fixed in version 0.21.0.

A quadratic-time denial of service vulnerability exists in re2js when using the opt-in LOOKBEHINDS flag with repeated-matching APIs such as matcher().find(), matchAll(), split(), or replaceAll(). This flaw causes the regex engine to restart scanning from the beginning of the input on every find call, resulting in quadratic time complexity and severe CPU consumption on large inputs. The issue affects re2js versions from 2.2.0 up to but not including 2.8.7 and is fixed in version 2.8.7.

Vue I18n is the internationalization plugin for Vue.js. From 9.0.0-beta.5 until 11.4.14 and 12.0.0-alpha.5, enabling escapeParameter, called escapeParameterHtml in the Legacy API, does not escape named interpolation values when the same translation call supplies both list and named values because escapeParams() processes only the list branch. Applications that render translations as HTML and pass untrusted named values with a list can insert attacker-controlled markup, including phishing links, forms, and layout changes, and can permit script execution when combined with the srcdoc sanitizer bypass or on releases without the sanitizer. This issue is fixed in versions 11.4.14 and 12.0.0-alpha.5.

CVE-2026-118615 is a high-severity OS command injection vulnerability in the Ultralytics product, specifically in the torch_safe_load function. This flaw allows remote attackers to execute arbitrary code by supplying malicious input that is improperly validated before being used in a system call. Exploitation requires user interaction, such as visiting a malicious webpage or opening a malicious file. The vulnerability affects version 8.4.65 of Ultralytics.

A memory leak vulnerability was identified and fixed in the Linux kernel's gpiolib subsystem within the function gpiod_set_array_value_complex(). The issue occurs on error paths where allocated bitmaps may not be freed properly after a failed call to gpiochip_set_multiple(), leading to potential memory leakage. Although the error path is unlikely, it is possible and has been addressed by deferring the return code check until after the bitmap is freed.

A vulnerability in the Linux kernel's AMDGPU driver caused a GEM object leak when the userptr ioctl call fails due to memory allocation errors (ENOMEM). This occurs because the error path skips necessary cleanup, leaving behind allocated objects and references.

In the Linux kernel, the following vulnerability has been resolved: drm/vc4: hdmi: Move packet RAM enable to PM runtime Audio can be triggered by the HPD handler and start up before video has been restored, calling vc4_hdmi_write_infoframe() for the audio infoframe. vc4_hdmi_write_infoframe() needs Packet RAM to be on to store the infoframe, however, if the video hasn't been enabled, vc4_hdmi_encoder_post_crtc_enable() hasn't been called and therefore, the Packet RAM can be disabled by the time vc4_hdmi_write_infoframe() executes, causing the following splat: [ 201.570266] ------------[ cut here ]------------ [ 201.570293] Packet RAM has to be on to store the packet. [ 201.570367] WARNING: drivers/gpu/drm/vc4/vc4_hdmi.c:683 at vc4_hdmi_write_infoframe+0x404/0x494 [vc4], CPU#0: wireplumber/1606 [...] [ 201.658650] Hardware name: Raspberry Pi 4 Model B Rev 1.5 (DT) [...] [ 201.758499] Call trace: [ 201.760967] vc4_hdmi_write_infoframe+0x404/0x494 [vc4] (P) [ 201.766607] vc4_hdmi_write_audio_infoframe+0x1c/0x28 [vc4] [ 201.772247] write_infoframe+0xbc/0x140 [drm_display_helper] [ 201.777975] drm_atomic_helper_connector_hdmi_update_audio_infoframe+0x80/0xdc [drm_display_helper] [ 201.787140] vc4_hdmi_audio_prepare+0x4ac/0x570 [vc4] [ 201.792252] drm_connector_hdmi_audio_prepare+0x24/0x30 [drm_display_helper] [ 201.799390] hdmi_codec_prepare+0x100/0x160 [snd_soc_hdmi_codec] [ 201.805471] snd_soc_pcm_dai_prepare+0xd4/0x100 [snd_soc_core] [ 201.811375] __soc_pcm_prepare+0x60/0x12c [snd_soc_core] [ 201.816752] soc_pcm_prepare+0x34/0x58 [snd_soc_core] [ 201.821863] snd_pcm_do_prepare+0x70/0x8c [snd_pcm] [ 201.826798] snd_pcm_action_nonatomic+0xe4/0x174 [snd_pcm] [ 201.832350] snd_pcm_prepare+0xc8/0xd8 [snd_pcm] [ 201.837021] snd_pcm_common_ioctl+0x458/0x614 [snd_pcm] [ 201.842308] snd_pcm_ioctl+0x30/0x48 [snd_pcm] [ 201.846802] __arm64_sys_ioctl+0x88/0xd8 [ 201.850769] invoke_syscall+0x48/0xf4 [ 201.854470] el0_svc_common+0x80/0xd8 [ 201.858171] do_el0_svc+0x1c/0x28 [ 201.861520] el0_svc+0x3c/0xb0 [ 201.864605] el0t_64_sync_handler+0x68/0xdc [ 201.868834] el0t_64_sync+0x198/0x19c [ 201.872536] ---[ end trace 0000000000000000 ]--- Considering that Packet RAM enable is essentially a power management configuration, move its enabling/disabling to the Runtime PM hooks. Note that post_crtc_disable() still stops all infoframes, but keeps Packet RAM enabled, leaving it to be disabled by runtime suspend.

CVE-2026-99205 is a Linux kernel vulnerability involving the scheduler core where a race condition during task class changes can cause the CPU to idle despite having runnable tasks. This occurs because the scheduler's next_class indicator does not update correctly when a queued task changes scheduling class, leading to lost rescheduling signals and CPU idle loops. The issue has been fixed by ensuring wakeup_preempt() is called during class changes to properly update scheduling state and rescheduling needs.

In the Linux kernel, the following vulnerability has been resolved: ocfs2/dlm: Protect the recovery list during debugfs reads Recovery participant records must remain alive while debug_state_print() walks reco.node_data and formats their fields. The formatter holds dlm->spinlock, but the recovery participant list is protected by dlm_reco_state_lock. In particular, dlm_destroy_recovery_area() detaches the list under dlm_reco_state_lock and frees the detached records after releasing it. A concurrent debugfs open can therefore read freed memory. Protect the participant traversal and field reads in debug_state_print() with dlm_reco_state_lock, matching the existing list writers. This also serializes the traversal against list_add_tail() during recovery-area initialization. Make the existing lock available to the debug code through dlmcommon.h; the lock remains internal to the OCFS2 DLM module. Release dlm->spinlock after formatting the other domain state and before acquiring dlm_reco_state_lock, so the debug reader does not nest the two locks. Leave recovery list insertion, detachment and freeing unchanged. KASAN report as below: BUG: KASAN: slab-use-after-free in debug_state_open+0x1169/0x12d0 Read of size 4 at addr ffff88810662ef80 by task dlm-state-stres/896 CPU: 1 UID: 0 PID: 896 Comm: dlm-state-stres Not tainted 7.3.0-rc4-next-20260921-pmb-ocfs2-functional-v1+ #1 PREEMPT(lazy) Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x93/0xd0 print_report+0xce/0x630 ? debug_state_open+0x1169/0x12d0 ? srso_alias_return_thunk+0x5/0xfbef5 ? __virt_addr_valid+0x20e/0x420 ? debug_state_open+0x1169/0x12d0 kasan_report+0xe0/0x110 ? debug_state_open+0x1169/0x12d0 debug_state_open+0x1169/0x12d0 ? __pfx_debug_state_open+0x10/0x10 full_proxy_open_regular+0x193/0x310 do_dentry_open+0x595/0x12d0 ? __pfx_full_proxy_open_regular+0x10/0x10 vfs_open_consume+0xd1/0x400 ? srso_alias_return_thunk+0x5/0xfbef5 path_openat+0x18d0/0x2020 ? __pfx_path_openat+0x10/0x10 do_file_open+0x21e/0x470 ? __pfx_do_file_open+0x10/0x10 ? _raw_spin_unlock+0x23/0x40 ? srso_alias_return_thunk+0x5/0xfbef5 ? alloc_fd+0x3a6/0x6b0 do_sys_openat2+0xf4/0x1b0 ? __pfx_do_sys_openat2+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? __fput+0x5b5/0xa60 __x64_sys_openat+0x136/0x1e0 ? __pfx___x64_sys_openat+0x10/0x10 do_syscall_64+0x114/0x620 entry_SYSCALL_64_after_hwframe+0x77/0x7f [Register dump omitted.] </TASK> Allocated by task 880: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 __kasan_kmalloc+0xaa/0xb0 __kmalloc_cache_noprof+0x28d/0x610 dlm_remaster_locks+0x147/0x1d90 dlm_do_recovery+0xde1/0x1580 dlm_recovery_thread+0x109/0x300 kthread+0x351/0x460 ret_from_fork+0x659/0x940 ret_from_fork_asm+0x1a/0x30 Freed by task 880: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3b/0x60 __kasan_slab_free+0x5f/0x80 kfree+0x308/0x580 dlm_destroy_recovery_area+0x285/0x460 dlm_remaster_locks+0x17c4/0x1d90 dlm_do_recovery+0xde1/0x1580 dlm_recovery_thread+0x109/0x300 kthread+0x351/0x460 ret_from_fork+0x659/0x940 ret_from_fork_asm+0x1a/0x30 The buggy address belongs to the object at ffff88810662ef80 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 0 bytes inside of freed 32-byte region [ffff88810662ef80, ffff88810662efa0) [Page and memory-state dumps omitted.]

In the Linux kernel, the following vulnerability has been resolved: pipe: preserve existing fasync readers on writer setup failure F_SETFL and FIOASYNC decide whether to invoke ->fasync() before pipe_fasync() takes pipe->mutex. Two enables of one O_RDWR FIFO can therefore both enter the callback. fasync_helper() allocates before checking for an existing entry. If the first enable installs both entries, a second enable can update the reader entry and then fail the allocation for the writer entry. The error path removes the pre-existing reader entry, clearing FASYNC while the writer entry remains registered. __fput() then skips ->fasync(), so a later pipe notification can dereference the freed file or its f_owner. An unprivileged memory-pressure reproducer triggers a KASAN slab-use-after-free in send_sigio() through this path. Keep the reader helper's result and undo the registration only if this call added it. The pipe mutex serializes changes to both lists, so a failed new registration still removes its reader, while a failed duplicate preserves the existing registrations and FASYNC. Successful duplicate enables continue to update fa_fd as before.

In the Linux kernel, the following vulnerability has been resolved: calipso: keep BIG TCP payload_len in calipso_skbuff_setattr() calipso_skbuff_setattr() adjusts payload_len by the length of the option it inserts or resizes: payload = ntohs(ip6_hdr->payload_len); ip6_hdr->payload_len = htons(payload + len_delta); GRO can build BIG TCP packets larger than IPV6_MAXPLEN, and stores payload_len == 0 for them; ipv6_payload_len() then falls back to skb->len. For such a packet forwarded to a destination mapped to CALIPSO, the code above writes len_delta (or 65536 + len_delta when shrinking) into payload_len, and ipv6_payload_len() no longer falls back to skb->len. nf_tables, conntrack and sch_cake rely on it. The same arithmetic also wraps when a packet grows past IPV6_MAXPLEN, and a BIG TCP packet that shrinks below IPV6_MAXPLEN should get its real length back. Set payload_len from the skb length with ipv6_set_payload_len(), which stores 0 above IPV6_MAXPLEN and the real length otherwise, as ipv6_gro_complete() does. The network header was just reset to skb->data, so skb->len - sizeof(*ip6_hdr) is the payload length. Tested on one kernel (arm64, QEMU) with SELinux permissive, a minimal mdp-generated policy (network_peer_controls=1), "netlabelctl calipso add pass doi:16" and a NetLabel mapping of fd00:2::/64 to CALIPSO DOI 16. calipso_skbuff_setattr() was called through netlbl_skbuff_setattr() from a test-only debugfs hook (not part of this patch) adding a level-only label; payload_len after the call: case before fix after fix real length 1000, unlabeled 1016 1016 1016 70000 GSO, payload_len 0 16 0 70016 65530 GSO, grows past MAXPLEN 10 0 65546 65540 GSO with a 24 byte hop header, shrinks below MAXPLEN 65528 65532 65532 1000 with a 24 byte hop header 992 992 992 (0 means ipv6_payload_len() returns the real length.) On the forward path, with a client injecting unlabeled UDP through a router to a server, the router adds the CALIPSO option and the server delivers all datagrams (Udp6InDatagrams 5, Ip6InTruncatedPkts 0) with this patch.

In the Linux kernel, the following vulnerability has been resolved: unicode: free the map after a grace period generic_ci_d_hash() and generic_ci_d_compare() read sb->s_encoding and dereference the unicode map while a pathwalk in rcu mode holds nothing but rcu_read_lock(). The filesystems that use them, ext4, f2fs and tmpfs, drop the map with utf8_unload() from ->put_super(), which runs when the last reference to the mount goes away. A lookup that is still inside such a filesystem at that point reads a freed map. With a pathwalk held up in utf8_casefold_hash() while the last reference to a casefolded tmpfs goes away: BUG: KASAN: slab-use-after-free in utf8nlookup+0x74c/0x950 Read of size 8 at addr ff110001030fe658 by task walker/98 Call Trace: <TASK> utf8nlookup+0x74c/0x950 utf8byte+0x160/0x1560 utf8_casefold_hash+0x167/0x230 generic_ci_d_hash+0xdd/0x1c0 link_path_walk+0x11ad/0x1d30 path_lookupat+0x63/0xb00 filename_lookup+0x1f1/0x5b0 vfs_statx+0xd7/0x3b0 [...] Allocated by task 94: __kmalloc_cache_noprof+0x249/0x560 utf8_load+0x4e/0x570 shmem_parse_opt_casefold.isra.0+0x92/0x270 [...] Freed by task 97: kfree+0x1db/0x5b0 shmem_put_super+0x72/0x170 generic_shutdown_super+0x14c/0x530 kill_anon_super+0x3a/0x60 deactivate_locked_super+0x9c/0xf0 cleanup_mnt+0x9f/0x130 So far that has been hard to hit. umount(2) waits for a grace period in namespace_unlock() before it drops the mount, so only a mount whose last reference goes away elsewhere, like the close of a file or a chdir out of a lazily unmounted directory, can race a walker. So it is reachable. Delay the free until a grace period has passed. The map and the data table it holds a reference to then outlive any pathwalk that found the superblock before the mount went away. The reference on the data table module is dropped from the rcu callback as well. utf8-core is built in whenever CONFIG_UNICODE is set, so there is no module exit that would have to wait for the callbacks. Overlayfs points the s_encoding of an overlay at the map of its first layer without taking a reference of its own. That stays correct. The layer is held by the overlay, so its map is dropped only after the overlay is gone.

In the Linux kernel, the following vulnerability has been resolved: watch_queue: Fix note pool publication race in watch_queue_set_size() There is a race between watch_queue_set_size() and post_one_notification(). watch_queue_set_size() publishes wqueue->notes, notes_bitmap, nr_pages and nr_notes with plain stores, and post_one_notification() reads them with plain loads under a different lock, so nothing orders the four stores against the poster's loads: depending on the build, notes can be stored last (gcc 14 on x86-64 does this). Since keyctl_watch_key() lets a watch attach to a queue before it is sized, post_one_notification() can already be running on another CPU at that moment: it reads nr_notes > 0, passes its bounds check, and then reads notes while it is still NULL, dereferencing notes[0]. An unprivileged user triggers this reliably by watching one of its own keys through a notification pipe and racing ioctl(IOC_WATCH_QUEUE_SET_SIZE) on that pipe against keyctl(KEYCTL_SETPERM) on the key from another CPU, triggering: BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: 0010:post_one_notification.isra.0+0xa2/0x1e0 Call Trace: __post_watch_notification+0x148/0x180 keyctl_setperm_key+0x119/0x130 do_syscall_64+0x108/0x4c0 entry_SYSCALL_64_after_hwframe+0x77/0x7f Kernel panic - not syncing: Fatal exception in interrupt Fix this by publishing nr_notes last with smp_store_release(), and by reading it once with smp_load_acquire() in post_one_notification() before the bitmap and the page array are touched. A poster that observes a non-zero nr_notes then also observes the pool behind it; one that observes zero drops the notification as before.

In the Linux kernel, the following vulnerability has been resolved: KVM: nVMX: Reset MMU back to the root MMU if loading L2 state fails for !VM-Entry Reset the vCPU's MMU pointer back to the root MMU if loading L2 state fails in the "not from VM-Entry" case, i.e. when emulating RSM or handling KVM_SET_NESTED_STATE. Failure to unwind the MMU pointer results in KVM trying to run L1 with a nested MMU, and is especially problematic if the vCPU manages to free its nested state before the VM crashes. Constructing the root for a nested EPT MMU goes through vmcs12, which is dynamically allocated/freed when nVMX is enabled/disabled. And so if the nested state is freed with the MMU still pointing at the nested MMU, KVM will hit a NULL pointer deref when attempting to get L1=>L2 EPTP. BUG: kernel NULL pointer dereference, address: 0000000000000078 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 114a2d067 P4D 111743067 PUD 11141f067 PMD 0 Oops: Oops: 0000 [#1] SMP CPU: 20 UID: 1000 PID: 1272 Comm: nested_tdp_faul Not tainted 7.3.0-rc4-8c89f11d1a99b-sink-vm #1914 PREEMPTLAZY Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:nested_ept_get_eptp+0xb/0x10 [kvm_intel] Call Trace: <TASK> kvm_mmu_load+0xcd/0x870 [kvm] kvm_arch_vcpu_ioctl_run+0x18f5/0x1f80 [kvm] kvm_vcpu_ioctl+0x2c7/0x970 [kvm] __x64_sys_ioctl+0x90/0xd0 do_syscall_64+0x9c/0x4d0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x47491b </TASK> Modules linked in: kvm_intel kvm irqbypass CR2: 0000000000000078 ---[ end trace 0000000000000000 ]--- RIP: 0010:nested_ept_get_eptp+0xb/0x10 [kvm_intel] [sean: write changelog]

In the Linux kernel, the following vulnerability has been resolved: fsnotify: prevent mark additions during connector teardown fsnotify_destroy_marks() keeps a reference to its current mark while it drops conn->lock to destroy the mark. This stabilizes the forward-walk cursor, but does not prevent a new mark from being inserted before it. For example, an inotify watch re-added after IN_IGNORED sorts before the old, detached mark for the same group. The walk can miss the replacement and then detach the entire connector from the object. The replacement is still on its group's marks_list and, for inotify, in the watch IDR. The group mutex no longer protects the connector's object from disappearing. An unprivileged fdinfo read racing the final detach can consequently call igrab(NULL): BUG: KASAN: null-ptr-deref in igrab+0x24/0x100 Write of size 4 at addr 0000000000000148 Call Trace: igrab+0x24/0x100 inotify_show_fdinfo+0x1dc/0x5e0 seq_show+0x397/0x690 Set a DESTROYING flag under conn->lock before starting the walk, and reject new marks on that connector with -ENOENT. The existing add-mark error paths undo the temporary group-list entry and the backend's watch allocation. Do not wait for teardown while holding the group mutex, which the destroyer needs. Once the old connector is detached, an add can install a fresh connector as before. This closes the insertion race for all object types using the common connector teardown, without changing the mark reference or SRCU lifetime rules.

In the Linux kernel, the following vulnerability has been resolved: ext4: free the sbi after a grace period ext4_get_link() follows a symlink that keeps its target in a data block in rcu pathwalk mode with ext4_getblk(EXT4_GET_BLOCKS_CACHED_NOWAIT). That reads s_mount_state in the ASSERT() of ext4_getblk() and again in ext4_es_lookup_extent(), and the lookup bumps the extent status hit or miss counter, all through sb->s_fs_info. ext4_put_super() destroys those counters, clears sb->s_fs_info and frees the sbi without waiting for a grace period. A pathwalk that is still in ext4_get_link() when the last reference to the mount goes away then dereferences a NULL s_fs_info, the freed sbi or the destroyed percpu counters. With a pathwalk held up in ext4_get_link() while the last reference goes away: KASAN: null-ptr-deref in range [0x00000000000000a8-0x00000000000000af] RIP: 0010:ext4_getblk+0xf0/0x640 Call Trace: <TASK> ext4_get_link+0x26c/0x410 pick_link+0xf96/0x1780 step_into_slowpath+0x9b8/0x1250 path_lookupat+0x484/0xb00 filename_lookup+0x1f1/0x5b0 vfs_statx+0xd7/0x3b0 vfs_fstatat+0x4d/0x90 __do_sys_newfstatat+0xa0/0x100 do_syscall_64+0x10e/0x5e0 entry_SYSCALL_64_after_hwframe+0x77/0x7f So far that has been hard to hit. umount(2) waits for a grace period in namespace_unlock() before it drops the mount, so only a mount whose last reference goes away elsewhere, like the close of a file or a chdir out of a lazily unmounted directory, can race a walker. Keep sb->s_fs_info and free the sbi together with the extent status counters after a grace period. Split the counters out of ext4_es_unregister_shrinker() for that. The shrinker still gets wasted in ext4_put_super(), the counters go with the sbi.

In the Linux kernel, the following vulnerability has been resolved: namespace: a mount that copy_tree() leaves out can't take over a lock Since commit c62a4766937e ("move_mount: transfer MNT_LOCKED") a mount can be moved beneath a locked mount. The lock moves from the old cover to the new mount which takes over the job of hiding what's under it and the old cover can be unmounted. That works as long as the new mount stays. But the caller picks the new mount and copy_tree() leaves a mount of a mount namespace file out of every copy made without CL_COPY_MNT_NS_FILE, together with everything mounted on it, and never looks at MNT_LOCKED. unshare(CLONE_NEWNS) and mount propagation make such copies. So a task that is root in its own user namespace gets rid of a locked cover on a file without a race and without touching the filesystem below it. It makes a child with a mount namespace of its own, binds the child's /proc/<pid>/ns/mnt beneath the cover with MOVE_MOUNT_BENEATH, which hands the lock to that bind, and calls unshare(CLONE_NEWNS). The new mount namespace has nothing on the file. That's the usual way to mask a single file, a bind of /dev/null or of an empty file. With a bind of an ordinary file the file stays covered. copy_tree() already refuses to leave out a locked unbindable mount with -EPERM since commit df7342b24018 ("mount: Don't allow copying MNT_UNBINDABLE|MNT_LOCKED mounts"). Do the same for a locked mount of a mount namespace file. That also covers a tree copied with CL_COPY_MNT_NS_FILE and attached into a mount namespace of another user namespace where lock_mnt_tree() locks it. Note that unshare(CLONE_NEWNS) and clone(CLONE_NEWNS) fail with EPERM from such a mount namespace from then on. The mount can't be left out and it can't be unmounted. And refuse to move a mount of a mount namespace file beneath a locked mount in the first place. Otherwise the task ends up with a mount it can't unmount and an unshare() that fails for good. Chris also found a second mount that goes away by itself, a clone of an automounted mount that shrink_submounts() took along with its parent. Commit f78ddcc87224 ("namespace: never expire a locked mount") took care of that one. Chris's reproducer is appended. Mode nsfile reads SECRET after the unshare() on 7.3-rc7, with this patch the move_mount() fails with EINVAL and the file stays covered. nsfile-control uses an ordinary file and reads MASK both ways. // SPDX-License-Identifier: GPL-2.0 /* * Get rid of a locked cover with MOVE_MOUNT_BENEATH. * * The "admin" (root) makes a tmpfs W: * W/D file, holds SECRET, covered by a bind of a file with MASK * W/Dd/inner file, holds SECRET, Dd is covered by a bind of a directory * whose "inner" holds MASK * W/own directory of uid 1000 with the file "mine" and the * directory "minedir", whose "inner" holds MINE * W/dbg debugfs, mode 755. dbg/tracing is an automount point * The "attacker" is uid 1000. It enters a new user namespace with a new mount * namespace, so W and both covers are locked there. * * usage: prog MODE * plain put a bind of own/mine beneath the cover of D, unmount the cover * nsfile put a bind of the mount namespace file of a child beneath the * cover of D, then unshare(CLONE_NEWNS) * nsfile-control the same with a bind of own/mine * shrink put a bind of the automounted tracefs beneath the cover of Dd, * unmount the cover, put a tmpfs beneath W, call umount(W), which fails * shrink-control the same with a bind of own/minedir * The environment variable AUTOMOUNT_DIR names another automount point for "shrink". */ #define _GNU_SOURCE #include <errno.h> #include <fcntl.h> #include <grp.h> #include <sched.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> ---truncated---

In the Linux kernel, the following vulnerability has been resolved: sctp: revalidate output stream after association connect wait When message interleaving is enabled, the first send waits for association establishment before building its data chunks. The wait drops the socket lock, and handshake processing can reduce the output stream count to the peer-advertised inbound stream count. sctp_stream_init() then frees the extension of every removed stream. The sender resumes with the stream that it checked before the wait. If the peer removed that stream, sctp_outq_tail() later dereferences its NULL extension. Fatal-oops policies then panic the host. KASAN: null-ptr-deref in range [0x38-0x3f] RIP: sctp_outq_tail+0x49e/0xaa0 Call Trace: sctp_primitive_SEND sctp_sendmsg_to_asoc sctp_sendmsg A range check alone is insufficient. Stream reconfiguration can grow the output count again while the lock is released without recreating extensions freed by the earlier shrink. The stream can then be in range while its extension remains NULL. The send-buffer wait has the same issue. Factor the range and extension checks into a helper and repeat both after each send-path wait that drops the socket lock. Once the lock is reacquired, the validation remains stable through data creation and queueing. If validation fails after the connect wait, the auto-created association is already established. Return ESRCH so the existing caller path keeps it under state-machine ownership instead of freeing it directly, which would leave protocol, counter and socket state inconsistent.