CVE-2025-21721

Medium

In the Linux kernel, the following vulnerability has been resolved: nilfs2: handle errors that nilfs_prepare_chunk() may return Patch series "nilfs2: fix issues with rename operations". This series fixes BUG_ON check failures reported by syzbot around rename operations, and a minor behavioral issue where the mtime of a child directory changes when it is renamed instead of moved. This patch (of 2): The directory manipulation routines nilfs_set_link() and nilfs_delete_entry() rewrite the directory entry in the folio/page previously read by nilfs_find_entry(), so error handling is omitted on the assumption that nilfs_prepare_chunk(), which prepares the buffer for rewriting, will always succeed for these. And if an error is returned, it triggers the legacy BUG_ON() checks in each routine. This assumption is wrong, as proven by syzbot: the buffer layer called by nilfs_prepare_chunk() may call nilfs_get_block() if necessary, which may fail due to metadata corruption or other reasons. This has been there all along, but improved sanity checks and error handling may have made it more reproducible in fuzzing tests. Fix this issue by adding missing error paths in nilfs_set_link(), nilfs_delete_entry(), and their caller nilfs_rename().

Package Linux Kernel
Published 2025-02-27
Last modified 2025-11-03
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

Weakness type

CWE-617

CVE-2025-21721 is classified as CWE-617

See CWE-617 on MITRE CWE for full details on this weakness type.

Affected versions

Linux kernel versions 2.6.30 and later are affected. Fixed in 5.4.291, 5.10.235, 5.15.179, 6.1.131, 6.6.80, 6.12.13, 6.13.2, 6.14 and their respective stable series.

Affected from
≥ 2.6.30
Fixed in
✓ 5.4.291 5.4.x ✓ 5.10.235 5.10.x ✓ 5.15.179 5.15.x ✓ 6.1.131 6.1.x ✓ 6.6.80 6.6.x ✓ 6.12.13 6.12.x ✓ 6.13.2 6.13.x ✓ 6.14

References

The following references provide additional information about CVE-2025-21721 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

8 patch commits total View all on NVD

Frequently asked questions

  • What is CVE-2025-21721?

    CVE-2025-21721 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 2.6.30 onward and has been patched in 5.4.291, 5.10.235, 5.15.179 and others. CVE-2025-21721 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2025-21721?

    CVE-2025-21721 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-2025-21721?

    Yes — CVE-2025-21721 has been patched. Fixed versions include 5.4.291, 5.10.235, 5.15.179 and others. If you are running Linux kernel 2.6.30 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2025-21721 actively exploited?

    No — CVE-2025-21721 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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