VulnerabilityPublished 6 Dec 2025Updated 8 Oct 2026

CVE-2025-40273: Linux kernel · NFSD: free copynotify stateid in nfs4_free_ol_stateid()

Affects Linux kernelSource GCVE Database

Not known to be exploited · CVSS 8.8 High · fixed in 5.15.0-1103.110~20.04.1 : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

8.8High

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

EPSS: 0.4% chance of exploitation in 30 days – higher than 36% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 5.15.0-1103.110~20.04.1, 5.15.0-1110.119~20.04.1, 5.15.0-1103.112~20.04.1 +69

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
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: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
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 6 Dec 2025
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.

Affected software

Product	Affected	Fixed in
Ubuntu 25.10linux`pkg:deb/ubuntu/linux?arch=source&distro=questing`Other threats	Affected <6.17.0-14.14	Fixed in 6.17.0-14.14
Ubuntu 25.10linux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=questing`Other threats	Affected <6.17.0-1007.7	Fixed in 6.17.0-1007.7
Ubuntu 25.10linux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=questing`Other threats	Affected <6.17.0-1008.8	Fixed in 6.17.0-1008.8
Ubuntu 25.10linux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questing`Other threats	Affected 6.17.0-1003.3 – 6.17.0-1017.17 10 affected builds	Fixed in–
Ubuntu 25.10linux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=questing`Other threats	Affected <6.17.0-1007.7	Fixed in 6.17.0-1007.7
Ubuntu 25.10linux-oracle`pkg:deb/ubuntu/linux-oracle?arch=source&distro=questing`Other threats	Affected <6.17.0-1007.7	Fixed in 6.17.0-1007.7

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: NFSD: free copynotify stateid in nfs4_free_ol_stateid() Typically copynotify stateid is freed either when parent's stateid is being close/freed or in nfsd4_laundromat if the stateid hasn't been used in a lease period. However, in case when the server got an OPEN (which created a parent stateid), followed by a COPY_NOTIFY using that stateid, followed by a client reboot. New client instance while doing CREATE_SESSION would force expire previous state of this client. It leads to the open state being freed thru release_openowner-> nfs4_free_ol_stateid() and it finds that it still has copynotify stateid associated with it. We currently print a warning and is triggerred WARNING: CPU: 1 PID: 8858 at fs/nfsd/nfs4state.c:1550 nfs4_free_ol_stateid+0xb0/0x100 [nfsd] This patch, instead, frees the associated copynotify stateid here. If the parent stateid is freed (without freeing the copynotify stateids associated with it), it leads to the list corruption when laundromat ends up freeing the copynotify state later. [ 1626.839430] Internal error: Oops - BUG: 00000000f2000800 [#1] SMP [ 1626.842828] Modules linked in: nfnetlink_queue nfnetlink_log bluetooth cfg80211 rpcrdma rdma_cm iw_cm ib_cm ib_core nfsd nfs_acl lockd grace nfs_localio ext4 crc16 mbcache jbd2 overlay uinput snd_seq_dummy snd_hrtimer qrtr rfkill vfat fat uvcvideo snd_hda_codec_generic videobuf2_vmalloc videobuf2_memops snd_hda_intel uvc snd_intel_dspcfg videobuf2_v4l2 videobuf2_common snd_hda_codec snd_hda_core videodev snd_hwdep snd_seq mc snd_seq_device snd_pcm snd_timer snd soundcore sg loop auth_rpcgss vsock_loopback vmw_vsock_virtio_transport_common vmw_vsock_vmci_transport vmw_vmci vsock xfs 8021q garp stp llc mrp nvme ghash_ce e1000e nvme_core sr_mod nvme_keyring nvme_auth cdrom vmwgfx drm_ttm_helper ttm sunrpc dm_mirror dm_region_hash dm_log iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi fuse dm_multipath dm_mod nfnetlink [ 1626.855594] CPU: 2 UID: 0 PID: 199 Comm: kworker/u24:33 Kdump: loaded Tainted: G B W 6.17.0-rc7+ #22 PREEMPT(voluntary) [ 1626.857075] Tainted: [B]=BAD_PAGE, [W]=WARN [ 1626.857573] Hardware name: VMware, Inc. VMware20,1/VBSA, BIOS VMW201.00V.24006586.BA64.2406042154 06/04/2024 [ 1626.858724] Workqueue: nfsd4 laundromat_main [nfsd] [ 1626.859304] pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) [ 1626.860010] pc : __list_del_entry_valid_or_report+0x148/0x200 [ 1626.860601] lr : __list_del_entry_valid_or_report+0x148/0x200 [ 1626.861182] sp : ffff8000881d7a40 [ 1626.861521] x29: ffff8000881d7a40 x28: 0000000000000018 x27: ffff0000c2a98200 [ 1626.862260] x26: 0000000000000600 x25: 0000000000000000 x24: ffff8000881d7b20 [ 1626.862986] x23: ffff0000c2a981e8 x22: 1fffe00012410e7d x21: ffff0000920873e8 [ 1626.863701] x20: ffff0000920873e8 x19: ffff000086f22998 x18: 0000000000000000 [ 1626.864421] x17: 20747562202c3839 x16: 3932326636383030 x15: 3030666666662065 [ 1626.865092] x14: 6220646c756f6873 x13: 0000000000000001 x12: ffff60004fd9e4a3 [ 1626.865713] x11: 1fffe0004fd9e4a2 x10: ffff60004fd9e4a2 x9 : dfff800000000000 [ 1626.866320] x8 : 00009fffb0261b5e x7 : ffff00027ecf2513 x6 : 0000000000000001 [ 1626.866938] x5 : ffff00027ecf2510 x4 : ffff60004fd9e4a3 x3 : 0000000000000000 [ 1626.867553] x2 : 0000000000000000 x1 : ffff000096069640 x0 : 000000000000006d [ 1626.868167] Call trace: [ 1626.868382] __list_del_entry_valid_or_report+0x148/0x200 (P) [ 1626.868876] _free_cpntf_state_locked+0xd0/0x268 [nfsd] [ 1626.869368] nfs4_laundromat+0x6f8/0x1058 [nfsd] [ 1626.869813] laundromat_main+0x24/0x60 [nfsd] [ 1626.870231] process_one_work+0x584/0x1050 [ 1626.870595] worker_thread+0x4c4/0xc60 [ 1626.870893] kthread+0x2f8/0x398 [ 1626.871146] ret_from_fork+0x10/0x20 [ 1626.871422] Code: aa1303e1 aa1403e3 910e8000 97bc55d7 (d4210000) [ 1626.871892] SMP: stopping secondary CPUs

GCVE source: db.gcve.eu
OSV ID: UBUNTU-CVE-2025-40273
Osv Schema Version: 1.7.0
Ecosystems: Ubuntu:16.04:LTS, Ubuntu:18.04:LTS, Ubuntu:20.04:LTS, Ubuntu:Pro:20.04:LTS, Ubuntu:22.04:LTS, Ubuntu:Nvidia-BlueField:22.04:LTS, Ubuntu:Pro:FIPS-preview:22.04:LTS, Ubuntu:Pro:FIPS-updates:22.04:LTS, Ubuntu:Pro:Realtime:22.04:LTS, Ubuntu:24.04:LTS, Ubuntu:Nvidia-BlueField:24.04:LTS, Ubuntu:Pro:FIPS-updates:24.04:LTS, Ubuntu:Pro:Realtime:24.04:LTS, Ubuntu:25.10

References

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