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VulnerabilityPublished Updated

CVE-2026-22980: Linux kernel · nfsd: provide locking for v4_end_grace

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in e8bfa2401d4c51eca6e48e9b33c798828ca9df61 : patch Linux kernel soon.

Data as of 26 Oct 2026, 10:24 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-06-16.

Patch
Available – fixed in e8bfa2401d4c51eca6e48e9b33c798828ca9df61, ca97360860eb02e3ae4ba42c19b439a0fcecbf06, ba4811c8b433bfa681729ca42cc62b6034f223b0 +4
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 23 Jan 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6, < e8bfa2401d4c51eca6e48e9b33c798828ca9df61
Fixed in
  • e8bfa2401d4c51eca6e48e9b33c798828ca9df61
LinuxLinuxAffected
  • ≥ 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6, < ca97360860eb02e3ae4ba42c19b439a0fcecbf06
Fixed in
  • ca97360860eb02e3ae4ba42c19b439a0fcecbf06
LinuxLinuxAffected
  • ≥ 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6, < ba4811c8b433bfa681729ca42cc62b6034f223b0
Fixed in
  • ba4811c8b433bfa681729ca42cc62b6034f223b0
LinuxLinuxAffected
  • ≥ 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6, < 06600719d0f7a723811c45e4d51f5b742f345309
Fixed in
  • 06600719d0f7a723811c45e4d51f5b742f345309
LinuxLinuxAffected
  • ≥ 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6, < 2857bd59feb63fcf40fe4baf55401baea6b4feb4
Fixed in
  • 2857bd59feb63fcf40fe4baf55401baea6b4feb4
LinuxLinuxAffected
  • ≥ 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6, < 53f07d095e7e680c5e4569a55a019f2c0348cdc6
Fixed in
  • 53f07d095e7e680c5e4569a55a019f2c0348cdc6

Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: provide locking for v4_end_grace Writing to v4_end_grace can race with server shutdown and result in memory being accessed after it was freed - reclaim_str_hashtbl in particularly. We cannot hold nfsd_mutex across the nfsd4_end_grace() call as that is held while client_tracking_op->init() is called and that can wait for an upcall to nfsdcltrack which can write to v4_end_grace, resulting in a deadlock. nfsd4_end_grace() is also called by the landromat work queue and this doesn't require locking as server shutdown will stop the work and wait for it before freeing anything that nfsd4_end_grace() might access. However, we must be sure that writing to v4_end_grace doesn't restart the work item after shutdown has already waited for it. For this we add a new flag protected with nn->client_lock. It is set only while it is safe to make client tracking calls, and v4_end_grace only schedules work while the flag is set with the spinlock held. So this patch adds a nfsd_net field "client_tracking_active" which is set as described. Another field "grace_end_forced", is set when v4_end_grace is written. After this is set, and providing client_tracking_active is set, the laundromat is scheduled. This "grace_end_forced" field bypasses other checks for whether the grace period has finished. This resolves a race which can result in use-after-free.

References

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