CVE-2026-22989

Medium

In the Linux kernel, the following vulnerability has been resolved: nfsd: check that server is running in unlock_filesystem If we are trying to unlock the filesystem via an administrative interface and nfsd isn't running, it crashes the server. This happens currently because nfsd4_revoke_states() access state structures (eg., conf_id_hashtbl) that has been freed as a part of the server shutdown. [ 59.465072] Call trace: [ 59.465308] nfsd4_revoke_states+0x1b4/0x898 [nfsd] (P) [ 59.465830] write_unlock_fs+0x258/0x440 [nfsd] [ 59.466278] nfsctl_transaction_write+0xb0/0x120 [nfsd] [ 59.466780] vfs_write+0x1f0/0x938 [ 59.467088] ksys_write+0xfc/0x1f8 [ 59.467395] __arm64_sys_write+0x74/0xb8 [ 59.467746] invoke_syscall.constprop.0+0xdc/0x1e8 [ 59.468177] do_el0_svc+0x154/0x1d8 [ 59.468489] el0_svc+0x40/0xe0 [ 59.468767] el0t_64_sync_handler+0xa0/0xe8 [ 59.469138] el0t_64_sync+0x1ac/0x1b0 Ensure this can't happen by taking the nfsd_mutex and checking that the server is still up, and then holding the mutex across the call to nfsd4_revoke_states().

Package Linux Kernel
Published 2026-01-23
Last modified 2026-02-26
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

5.5

out of 10
Medium
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected versions

Linux kernel versions 6.9 and later are affected. Fixed in 6.12.66, 6.18.6, 6.19 and their respective stable series.

Affected from
≥ 6.9
Fixed in
✓ 6.12.66 6.12.x ✓ 6.18.6 6.18.x ✓ 6.19

References

The following references provide additional information about CVE-2026-22989 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Frequently asked questions

  • What is CVE-2026-22989?

    CVE-2026-22989 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 6.9 onward and has been patched in 6.12.66, 6.18.6 and 6.19. CVE-2026-22989 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-22989?

    CVE-2026-22989 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H .

  • Is there a patch available for CVE-2026-22989?

    Yes — CVE-2026-22989 has been patched. Fixed versions include 6.12.66, 6.18.6 and 6.19. If you are running Linux kernel 6.9 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2026-22989 actively exploited?

    No — CVE-2026-22989 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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