NULL pointer dereference in Linux kernel - CVE-2026-72253

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Main Vulnerability Database Vulnerabilities #VU143344

NULL pointer dereference in Linux kernel - CVE-2026-72253

Published: August 16, 2026


Vulnerability identifier: #VU143344
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-2026-72253
CWE-ID: CWE-476
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a null pointer dereference in the nf_conntrack_sip SIP helper when processing traffic with sip_external_media enabled in subsystems where routing information is unavailable. A local user can send specially crafted network traffic to cause a denial of service.

The issue affects tc ingress and openvswitch when the sip_external_media module parameter is set to 1.


Affected software

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

How to mitigate CVE-2026-72253

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