CVE-2025-39927

Medium

In the Linux kernel, the following vulnerability has been resolved: ceph: fix race condition validating r_parent before applying state Add validation to ensure the cached parent directory inode matches the directory info in MDS replies. This prevents client-side race conditions where concurrent operations (e.g. rename) cause r_parent to become stale between request initiation and reply processing, which could lead to applying state changes to incorrect directory inodes. [ idryomov: folded a kerneldoc fixup and a follow-up fix from Alex to move CEPH_CAP_PIN reference when r_parent is updated: When the parent directory lock is not held, req->r_parent can become stale and is updated to point to the correct inode. However, the associated CEPH_CAP_PIN reference was not being adjusted. The CEPH_CAP_PIN is a reference on an inode that is tracked for accounting purposes. Moving this pin is important to keep the accounting balanced. When the pin was not moved from the old parent to the new one, it created two problems: The reference on the old, stale parent was never released, causing a reference leak. A reference for the new parent was never acquired, creating the risk of a reference underflow later in ceph_mdsc_release_request(). This patch corrects the logic by releasing the pin from the old parent and acquiring it for the new parent when r_parent is switched. This ensures reference accounting stays balanced. ]

Package Linux Kernel
Published 2025-10-01
Last modified 2026-01-14
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

4.7

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

Weakness type

CWE-362

CVE-2025-39927 is a Race Condition vulnerability

What is Race Condition?

The product contains a code sequence that can run concurrently with other code, creating unexpected states. Learn more on MITRE CWE

Affected versions

Linux kernel versions 2.6.34 and later are affected. Fixed in 6.12.48, 6.16.8, 6.17 and their respective stable series.

Affected from
≥ 2.6.34
Fixed in
✓ 6.12.48 6.12.x ✓ 6.16.8 6.16.x ✓ 6.17

References

The following references provide additional information about CVE-2025-39927 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-2025-39927?

    CVE-2025-39927 is a Medium severity Linux kernel vulnerability with a CVSS score of 4.7 out of 10 , classified as a Race Condition flaw (CWE-362) . It affects Linux kernel versions from 2.6.34 onward and has been patched in 6.12.48, 6.16.8 and 6.17. CVE-2025-39927 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2025-39927?

    CVE-2025-39927 has a CVSS score of 4.7 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H .

  • Is there a patch available for CVE-2025-39927?

    Yes — CVE-2025-39927 has been patched. Fixed versions include 6.12.48, 6.16.8 and 6.17. If you are running Linux kernel 2.6.34 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2025-39927 actively exploited?

    No — CVE-2025-39927 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

  • What is Race Condition (CWE-362)?

    The product contains a code sequence that can run concurrently with other code, creating unexpected states. View CWE-362 on MITRE CWE →

Back to
All CVEs
View on
NVD / NIST