Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel - CVE-2026-72338

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Main Vulnerability Database Vulnerabilities #VU143094

Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel - CVE-2026-72338

Published: August 16, 2026


Vulnerability identifier: #VU143094
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-72338
CWE-ID: CWE-367
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local privileged user to perform an out-of-bounds heap write.

The vulnerability exists due to a time-of-check time-of-use race condition leading to an out-of-bounds write in the act_pedit tc offload handling when sizing and filling a flow_rule buffer during cls_flower offload processing. A local privileged user can trigger concurrent action and classifier operations to perform an out-of-bounds heap write.

The written data is attacker-controlled and can corrupt an adjacent slab object.


Affected software

Linux kernel
Ubuntu
linux-gcp-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)

How to mitigate CVE-2026-72338

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux-gcp-7.0 (Ubuntu package) - addressed in versions 7.0.0-38.38~24.04.4, 7.0.0-1013.13~24.04.1, 7.0.0-1014.14~24.04.1
linux-azure-7.0 (Ubuntu package) - addressed in versions 7.0.0-1016.16~24.04.1, 7.0.0-1017.17~24.04.1

External References

Related Security Bulletins