VulnerabilityPublished 27 Dec 2024Updated 28 Oct 2026

CVE-2024-53177: Linux kernel · smb: prevent use-after-free due to open_cached_dir error paths

Affects Linux kernelSource GCVE Database

Not known to be exploited · CVSS 9.8 Critical · fixed in 6.8.0-1027.29~22.04.1 : patch Linux kernel as a priority.

Data as of 28 Oct 2026, 11:13 UTC

CVSS 3.1 base score

9.8Critical

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in 6.8.0-1027.29~22.04.1, 6.8.0-1027.32~22.04.1, 6.8.0-1028.30~22.04.1 +29

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 27 Dec 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Patches and advisories

Affected software

Product	Affected	Fixed in
Ubuntu 24.04 LTSlinux`pkg:deb/ubuntu/linux?arch=source&distro=noble`Other threats	Affected <6.8.0-58.60	Fixed in 6.8.0-58.60
Ubuntu 24.04 LTSlinux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=noble`Other threats	Affected <6.8.0-1027.29	Fixed in 6.8.0-1027.29
Ubuntu 24.04 LTSlinux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=noble`Other threats	Affected <6.8.0-1027.32	Fixed in 6.8.0-1027.32
Ubuntu 24.04 LTSlinux-azure-6.11`pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=noble`Other threats	Affected <6.11.0-1012.12~24.04.1	Fixed in 6.11.0-1012.12~24.04.1
Ubuntu 24.04 LTSlinux-azure-nvidia`pkg:deb/ubuntu/linux-azure-nvidia?arch=source&distro=noble`Other threats	Affected <6.8.0-1014.15	Fixed in 6.8.0-1014.15
Ubuntu 24.04 LTSlinux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=noble`Other threats	Affected <6.8.0-1028.30	Fixed in 6.8.0-1028.30

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

In the Linux kernel, the following vulnerability has been resolved: smb: prevent use-after-free due to open_cached_dir error paths If open_cached_dir() encounters an error parsing the lease from the server, the error handling may race with receiving a lease break, resulting in open_cached_dir() freeing the cfid while the queued work is pending. Update open_cached_dir() to drop refs rather than directly freeing the cfid. Have cached_dir_lease_break(), cfids_laundromat_worker(), and invalidate_all_cached_dirs() clear has_lease immediately while still holding cfids->cfid_list_lock, and then use this to also simplify the reference counting in cfids_laundromat_worker() and invalidate_all_cached_dirs(). Fixes this KASAN splat (which manually injects an error and lease break in open_cached_dir()): ================================================================== BUG: KASAN: slab-use-after-free in smb2_cached_lease_break+0x27/0xb0 Read of size 8 at addr ffff88811cc24c10 by task kworker/3:1/65 CPU: 3 UID: 0 PID: 65 Comm: kworker/3:1 Not tainted 6.12.0-rc6-g255cf264e6e5-dirty #87 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020 Workqueue: cifsiod smb2_cached_lease_break Call Trace: <TASK> dump_stack_lvl+0x77/0xb0 print_report+0xce/0x660 kasan_report+0xd3/0x110 smb2_cached_lease_break+0x27/0xb0 process_one_work+0x50a/0xc50 worker_thread+0x2ba/0x530 kthread+0x17c/0x1c0 ret_from_fork+0x34/0x60 ret_from_fork_asm+0x1a/0x30 </TASK> Allocated by task 2464: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 __kasan_kmalloc+0xaa/0xb0 open_cached_dir+0xa7d/0x1fb0 smb2_query_path_info+0x43c/0x6e0 cifs_get_fattr+0x346/0xf10 cifs_get_inode_info+0x157/0x210 cifs_revalidate_dentry_attr+0x2d1/0x460 cifs_getattr+0x173/0x470 vfs_statx_path+0x10f/0x160 vfs_statx+0xe9/0x150 vfs_fstatat+0x5e/0xc0 __do_sys_newfstatat+0x91/0xf0 do_syscall_64+0x95/0x1a0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Freed by task 2464: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3b/0x60 __kasan_slab_free+0x51/0x70 kfree+0x174/0x520 open_cached_dir+0x97f/0x1fb0 smb2_query_path_info+0x43c/0x6e0 cifs_get_fattr+0x346/0xf10 cifs_get_inode_info+0x157/0x210 cifs_revalidate_dentry_attr+0x2d1/0x460 cifs_getattr+0x173/0x470 vfs_statx_path+0x10f/0x160 vfs_statx+0xe9/0x150 vfs_fstatat+0x5e/0xc0 __do_sys_newfstatat+0x91/0xf0 do_syscall_64+0x95/0x1a0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Last potentially related work creation: kasan_save_stack+0x33/0x60 __kasan_record_aux_stack+0xad/0xc0 insert_work+0x32/0x100 __queue_work+0x5c9/0x870 queue_work_on+0x82/0x90 open_cached_dir+0x1369/0x1fb0 smb2_query_path_info+0x43c/0x6e0 cifs_get_fattr+0x346/0xf10 cifs_get_inode_info+0x157/0x210 cifs_revalidate_dentry_attr+0x2d1/0x460 cifs_getattr+0x173/0x470 vfs_statx_path+0x10f/0x160 vfs_statx+0xe9/0x150 vfs_fstatat+0x5e/0xc0 __do_sys_newfstatat+0x91/0xf0 do_syscall_64+0x95/0x1a0 entry_SYSCALL_64_after_hwframe+0x76/0x7e The buggy address belongs to the object at ffff88811cc24c00 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 16 bytes inside of freed 1024-byte region [ffff88811cc24c00, ffff88811cc25000)

References

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