CVE-2025-39927

Local inode-state corruption via stale parent race

Published Oct 1, 2025 · Updated Aug 5, 2026

A race condition in the Linux kernel CephFS client allows local users to corrupt inode state through concurrent path lookup and rename operations. ceph_d_revalidate() can retain a stale r_parent while rename() moves a dentry, causing reply processing to copy metadata and capabilities to the wrong inode. A local account with access to a mounted CephFS can trigger the race, exposing foreign metadata, corrupting permissions, and hanging client operations.

CVSS severity7.8
High
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A race condition in the Linux kernel CephFS client allows local users to corrupt inode state through concurrent path lookup and rename operations. ceph_d_revalidate() can retain a stale r_parent while rename() moves a dentry, causing reply processing to copy metadata and capabilities to the wrong inode. A local account with access to a mounted CephFS can trigger the race, exposing foreign metadata, corrupting permissions, and hanging client operations.

The record

CVE
CVE-2025-39927
Published
Oct 1, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-362, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 1, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.6.34
  2. Affected versionversion=9030aaf9bf0a1eee47a154c316c789e959638b0f <15f519e9f883b316d86e2bb6b767a023aafd9d83
  3. Affected versionversion=9030aaf9bf0a1eee47a154c316c789e959638b0f <2bfe45987eb346e299d9f763f9cd05f77011519f
  4. Affected versionversion=9030aaf9bf0a1eee47a154c316c789e959638b0f <db378e6f83ec705c6091c65d482d555edc2b0a72

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.34; version=9030aaf9bf0a1eee47a154c316c789e959638b0f <15f519e9f883b316d86e2bb6b767a023aafd9d83; version=9030aaf9bf0a1eee47a154c316c789e959638b0f <2bfe45987eb346e299d9f763f9cd05f77011519f; version=9030aaf9bf0a1eee47a154c316c789e959638b0f <db378e6f83ec705c6091c65d482d555edc2b0a72

Published CVSS scores

7.8Linux Kernel CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
4.7CISA ADPCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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