What is CVE-2025-21696?

CVE-2025-21696 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, affecting Linux kernel versions from 5.7 onward and patched in 6.12.11 and 6.13. CVE-2025-21696 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-21696?

CVE-2025-21696 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-2025-21696?

Yes, CVE-2025-21696 has been patched. Fixed versions include 6.12.11 and 6.13. If you are running Linux kernel 5.7 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-21696 actively exploited?

CVE-2025-21696 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2025-21696

Medium

In the Linux kernel, the following vulnerability has been resolved: mm: clear uffd-wp PTE/PMD state on mremap() When mremap()ing a memory region previously registered with userfaultfd as write-protected but without UFFD_FEATURE_EVENT_REMAP, an inconsistency in flag clearing leads to a mismatch between the vma flags (which have uffd-wp cleared) and the pte/pmd flags (which do not have uffd-wp cleared). This mismatch causes a subsequent mprotect(PROT_WRITE) to trigger a warning in page_table_check_pte_flags() due to setting the pte to writable while uffd-wp is still set. Fix this by always explicitly clearing the uffd-wp pte/pmd flags on any such mremap() so that the values are consistent with the existing clearing of VM_UFFD_WP. Be careful to clear the logical flag regardless of its physical form; a PTE bit, a swap PTE bit, or a PTE marker. Cover PTE, huge PMD and hugetlb paths.

Package Linux Kernel

Published 2025-02-12

Last modified 2025-10-01

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 5.7 and later are affected. Fixed in 6.12.11, 6.13 and their respective stable series.

Affected from

≥ 5.7

Fixed in

✓ 6.12.11 6.12.x ✓ 6.13

References

The following references provide additional information about CVE-2025-21696 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/0cef0bb836e3cfe00f08f9606c72abd72fe78ca3
Patch
Kernel patch commit
https://git.kernel.org/stable/c/310ac886d68de661c3a334198d8604b722d7fdf8
Patch

Details

CVE ID CVE-2025-21696

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2025-02-12

Modified 2025-10-01

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-21696?

CVE-2025-21696 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 5.7 onward and has been patched in 6.12.11 and 6.13. CVE-2025-21696 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-21696?

CVE-2025-21696 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-2025-21696?

Yes — CVE-2025-21696 has been patched. Fixed versions include 6.12.11 and 6.13. If you are running Linux kernel 5.7 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-21696 actively exploited?

No — CVE-2025-21696 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.