CVE-2025-71239

Audit-rule bypass via unclassified fchmodat2 calls

Published Mar 17, 2026 · Updated Mar 17, 2026

Audit-rule bypass in the Linux kernel allows local users to change file permissions without generating expected audit events through fchmodat2(). The audit subsystem's change-attribute syscall class omits fchmodat2(), so watch rules that record attribute changes do not match that call. Local low-privileged access and a configured audit watch are required; the result is lost security telemetry rather than direct file access beyond existing permissions.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Audit-rule bypass in the Linux kernel allows local users to change file permissions without generating expected audit events through fchmodat2(). The audit subsystem's change-attribute syscall class omits fchmodat2(), so watch rules that record attribute changes do not match that call. Local low-privileged access and a configured audit watch are required; the result is lost security telemetry rather than direct file access beyond existing permissions.

The record

CVE
CVE-2025-71239
Published
Mar 17, 2026
Updated
Mar 17, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1562.001
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 17, 2026Record 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3e762a03713e8c25ca0108c075d662c897fc0623
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3ee75b13ea5f05ff9adc784b2464825bd70eb119
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4f493a6079b588cf1f04ce5ed6cdad45ab0d53dc
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4fed776ca86378da7dd743a7b648e20b025ba8ef
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <57489a89657cc94bf6ad8427d1902daba9156aa1
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <91e27bc79c3bca93c06bf5a471d47df9a35b3741
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c4334c0d0e7d6f02ed93756fd4ba807e3d00c05f
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f714315d7d68898d03093f67285256a8770f903c

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3e762a03713e8c25ca0108c075d662c897fc0623; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3ee75b13ea5f05ff9adc784b2464825bd70eb119; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4f493a6079b588cf1f04ce5ed6cdad45ab0d53dc; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4fed776ca86378da7dd743a7b648e20b025ba8ef; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <57489a89657cc94bf6ad8427d1902daba9156aa1; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <91e27bc79c3bca93c06bf5a471d47df9a35b3741; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c4334c0d0e7d6f02ed93756fd4ba807e3d00c05f; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f714315d7d68898d03093f67285256a8770f903c

Published CVSS scores

3.3SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
4.8SUSECVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
5.5NIST NVDCVSS:3.1/AV:L/AC:L/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.

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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

T1562.001Impair Defenses: Disable or Modify Tools

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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