What is CVE-2025-21691?

CVE-2025-21691 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, affecting Linux kernel versions from 6.5 onward and patched in 6.6.75, 6.12.12, 6.13.1 and others. CVE-2025-21691 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-21691?

CVE-2025-21691 has a CVSS score of 5.5 out of 10, rated Medium severity. 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-2025-21691?

Yes, CVE-2025-21691 has been patched. Fixed versions include 6.6.75, 6.12.12, 6.13.1 and others. If you are running Linux kernel 6.5 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-21691 actively exploited?

CVE-2025-21691 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2025-21691

Medium

In the Linux kernel, the following vulnerability has been resolved: cachestat: fix page cache statistics permission checking When the 'cachestat()' system call was added in commit cf264e1329fb ("cachestat: implement cachestat syscall"), it was meant to be a much more convenient (and performant) version of mincore() that didn't need mapping things into the user virtual address space in order to work. But it ended up missing the "check for writability or ownership" fix for mincore(), done in commit 134fca9063ad ("mm/mincore.c: make mincore() more conservative"). This just adds equivalent logic to 'cachestat()', modified for the file context (rather than vma).

Package Linux Kernel

Published 2025-02-10

Last modified 2025-10-15

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 6.5 and later are affected. Fixed in 6.6.75, 6.12.12, 6.13.1, 6.14 and their respective stable series.

Affected from

≥ 6.5

Fixed in

✓ 6.6.75 6.6.x ✓ 6.12.12 6.12.x ✓ 6.13.1 6.13.x ✓ 6.14

References

The following references provide additional information about CVE-2025-21691 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Kernel patch commit
https://git.kernel.org/stable/c/5f537664e705b0bf8b7e329861f20128534f6a83
Patch
Kernel patch commit
https://git.kernel.org/stable/c/780ab8329672464984cf1344bd5c3993af0226c7
Patch
Kernel patch commit
https://git.kernel.org/stable/c/7d6405c13b0d8a8367cd8df63f118b619a3f0dd2
Patch

4 patch commits total View all on NVD

Details

CVE ID CVE-2025-21691

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2025-02-10

Modified 2025-10-15

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-21691?

CVE-2025-21691 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 6.5 onward and has been patched in 6.6.75, 6.12.12, 6.13.1 and others. CVE-2025-21691 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-21691?

CVE-2025-21691 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-2025-21691?

Yes — CVE-2025-21691 has been patched. Fixed versions include 6.6.75, 6.12.12, 6.13.1 and others. If you are running Linux kernel 6.5 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-21691 actively exploited?

No — CVE-2025-21691 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.