Use-after-free in Linux kernel - CVE-2026-72422

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Main Vulnerability Database Vulnerabilities #VU143027

Use-after-free in Linux kernel - CVE-2026-72422

Published: August 15, 2026


Vulnerability identifier: #VU143027
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-72422
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to a use-after-free in smb3_preauth_hash_rsp() when processing concurrent SMB2 NEGOTIATE requests on the same connection. A remote attacker can send concurrent SMB2 NEGOTIATE requests that trigger a race and dereference freed memory to cause a denial of service.

The issue is a race between the SMB2 NEGOTIATE handler and the response send path, where a NULL check can be bypassed by concurrent freeing of conn->preauth_info before dereference.


Affected software

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

How to mitigate CVE-2026-72422

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - addressed in versions 7.0.0-34.34, 7.0.0-34.34.1, 7.0.0-34.34~24.04.1, 7.0.0-1012.12~24.04.1, 7.0.0-1013.13, 7.0.0-1013.13~24.04.1, 7.0.0-1014.14, 7.0.0-1020.20
linux-gcp (Ubuntu package) - addressed in versions 7.0.0-1013.13, 7.0.0-1013.13~24.04.1, 7.0.0-1014.14

External References

Related Security Bulletins