What is CVE-2026-89658?

CVE-2026-89658 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10, affecting Linux kernel versions from 6.9 onward and patched in 6.12.109, 6.18.50, 7.2.4 and others. CVE-2026-89658 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-89658?

CVE-2026-89658 has a CVSS score of 9.8 out of 10, rated Critical severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2026-89658?

Yes, CVE-2026-89658 has been patched. Fixed versions include 6.12.109, 6.18.50, 7.2.4 and others. 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-2026-89658 actively exploited?

CVE-2026-89658 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-89658

Critical

In the Linux kernel, the following vulnerability has been resolved: NFSD: Prevent client use-after-free during NFSv4.0 revoked-state cleanup nfs40_clean_admin_revoked() takes a stateid reference under clp->cl_lock, drops nn->client_lock, and calls nfsd4_drop_revoked_stid(), which dereferences the stateid's client through s->sc_client->cl_lock. The stateid reference does not pin the client, so a teardown racing the dropped lock can free the client while nfsd4_drop_revoked_stid() is still using it. This cleanup runs from the laundromat, so a periodic sweep can race force_expire_client() driven by a write to the clients/<id>/ctl file. Skip a client that is already expiring and otherwise pin it with cl_rpc_users under client_lock before dropping the lock, matching nfsd4_revoke_states().

Package Linux Kernel

Published 2026-09-11

Last modified 2026-09-13

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

9.8

out of 10

Critical

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

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

Affected versions

Linux kernel versions 6.9 and later are affected. Fixed in 6.12.109, 6.18.50, 7.2.4, 7.3-rc1 and their respective stable series.

Affected from

≥ 6.9

Fixed in

✓ 6.12.109 6.12.x ✓ 6.18.50 6.18.x ✓ 7.2.4 7.2.x ✓ 7.3-rc1

References

4 total

Details

CVE ID CVE-2026-89658

Severity Critical

CVSS score 9.8 / 10

CVSS version 3.1

Published 2026-09-11

Modified 2026-09-13

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-89658?

CVE-2026-89658 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10 . It affects Linux kernel versions from 6.9 onward and has been patched in 6.12.109, 6.18.50, 7.2.4 and others. CVE-2026-89658 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-89658?

CVE-2026-89658 has a CVSS score of 9.8 out of 10, rated Critical severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Is there a patch available for CVE-2026-89658?

Yes. CVE-2026-89658 has been patched. Fixed versions include 6.12.109, 6.18.50, 7.2.4 and others. 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-2026-89658 actively exploited?

No. CVE-2026-89658 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.