CVE-2026-72379

Invalid file ownership via unchecked O_TMPFILE mapping

Published Aug 15, 2026 · Updated Aug 15, 2026

Incorrect ownership assignment in the Linux kernel allows local users to create O_TMPFILE inodes owned by UID -1 on idmapped mounts. vfs_tmpfile() omits fsuidgid_has_mapping(), so inode_init_owner() stores INVALID_UID or INVALID_GID when the mount mapping excludes the caller's IDs. The flaw requires an idmapped mount with an uncovered fsuid or fsgid and a filesystem supporting O_TMPFILE; the linkable inode can then enter the namespace with invalid ownership.

CVSS severity5.5
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

Incorrect ownership assignment in the Linux kernel allows local users to create O_TMPFILE inodes owned by UID -1 on idmapped mounts. vfs_tmpfile() omits fsuidgid_has_mapping(), so inode_init_owner() stores INVALID_UID or INVALID_GID when the mount mapping excludes the caller's IDs. The flaw requires an idmapped mount with an uncovered fsuid or fsgid and a filesystem supporting O_TMPFILE; the linkable inode can then enter the namespace with invalid ownership.

The record

CVE
CVE-2026-72379
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-708, T1222.002
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 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=5.13
  2. Affected versionversion=8e5389132ab429604c1a2459b52f0c849a71cc61 <47e434da476b5a8bcd1e6e52ab03c5ee7764ee78
  3. Affected versionversion=8e5389132ab429604c1a2459b52f0c849a71cc61 <503d0568a525b168d9aa5ca046ec72fc5477df84
  4. Affected versionversion=8e5389132ab429604c1a2459b52f0c849a71cc61 <539dce1144651f7976fa418e618b0b574bf15eeb
  5. Affected versionversion=8e5389132ab429604c1a2459b52f0c849a71cc61 <a2038514e69371eb493083a6a897ed20fcbb8acb
  6. Affected versionversion=8e5389132ab429604c1a2459b52f0c849a71cc61 <bac8fb0d60254846f3b56957435dcd870ae12948

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.13; version=8e5389132ab429604c1a2459b52f0c849a71cc61 <47e434da476b5a8bcd1e6e52ab03c5ee7764ee78; version=8e5389132ab429604c1a2459b52f0c849a71cc61 <503d0568a525b168d9aa5ca046ec72fc5477df84; version=8e5389132ab429604c1a2459b52f0c849a71cc61 <539dce1144651f7976fa418e618b0b574bf15eeb; version=8e5389132ab429604c1a2459b52f0c849a71cc61 <a2038514e69371eb493083a6a897ed20fcbb8acb; version=8e5389132ab429604c1a2459b52f0c849a71cc61 <bac8fb0d60254846f3b56957435dcd870ae12948

Published CVSS scores

5.5OracleCVSS: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

CWE-708Incorrect Ownership Assignment
T1222.002File and Directory Permissions Modification: Linux and Mac Permissions

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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