CVE-2025-40055

Kernel memory corruption via cluster connection double-free

Published Oct 28, 2025 · Updated Oct 28, 2025

Double-free in the OCFS2 userspace cluster connection path in Linux allows local users to corrupt kernel memory during connection failure. The user_cluster_connect error path calls user_cluster_disconnect, which frees conn->cc_private, and then frees its lc alias a second time. Reachability requires low-privileged local access, the OCFS2 userspace cluster stack, and a connection error; published sources do not identify whether the resulting availability loss is a crash, hang, or reboot.

CVSS severity6.8
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Double-free in the OCFS2 userspace cluster connection path in Linux allows local users to corrupt kernel memory during connection failure. The user_cluster_connect error path calls user_cluster_disconnect, which frees conn->cc_private, and then frees its lc alias a second time. Reachability requires low-privileged local access, the OCFS2 userspace cluster stack, and a connection error; published sources do not identify whether the resulting availability loss is a crash, hang, or reboot.

The record

CVE
CVE-2025-40055
Published
Oct 28, 2025
Updated
Oct 28, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 28, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 28, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=3.14
  2. Affected versionversion=c994c2ebdbbc391a42f177c8eb7882ebf3f142d8 <694d5b401036a614f8080085a9de6f86ff0742dc
  3. Affected versionversion=c994c2ebdbbc391a42f177c8eb7882ebf3f142d8 <7e76fe9dfadbc00364d7523d5a109e9d3e4a7db2
  4. Affected versionversion=c994c2ebdbbc391a42f177c8eb7882ebf3f142d8 <827c8efa0d1afe817b90f3618afff552e88348d2
  5. Affected versionversion=c994c2ebdbbc391a42f177c8eb7882ebf3f142d8 <892f41e12c8689130d552a9eb2b77bafd26484ab
  6. Affected versionversion=c994c2ebdbbc391a42f177c8eb7882ebf3f142d8 <8f45f089337d924db24397f55697cda0e6960516
  7. Affected versionversion=c994c2ebdbbc391a42f177c8eb7882ebf3f142d8 <bfe011297ddd2d0cd64752978baaa0c04cd20573

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3.14; version=c994c2ebdbbc391a42f177c8eb7882ebf3f142d8 <694d5b401036a614f8080085a9de6f86ff0742dc; version=c994c2ebdbbc391a42f177c8eb7882ebf3f142d8 <7e76fe9dfadbc00364d7523d5a109e9d3e4a7db2; version=c994c2ebdbbc391a42f177c8eb7882ebf3f142d8 <827c8efa0d1afe817b90f3618afff552e88348d2; version=c994c2ebdbbc391a42f177c8eb7882ebf3f142d8 <892f41e12c8689130d552a9eb2b77bafd26484ab; version=c994c2ebdbbc391a42f177c8eb7882ebf3f142d8 <8f45f089337d924db24397f55697cda0e6960516; version=c994c2ebdbbc391a42f177c8eb7882ebf3f142d8 <bfe011297ddd2d0cd64752978baaa0c04cd20573

Published CVSS scores

0.0OracleCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:N
5.5SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
6.8SUSECVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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

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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