Use-after-free in Linux kernel - CVE-2026-98441

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Main Vulnerability Database Vulnerabilities #VU156739

Use-after-free in Linux kernel - CVE-2026-98441

Published: October 22, 2026


Vulnerability identifier: #VU156739
CSH Severity: Low
CVSS v4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-98441
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to cause kernel memory corruption and potentially a denial of service.

The vulnerability exists due to use-after-free in the Linux kernel act_ct connection tracking action when cloned packets share an unconfirmed connection tracking entry and are processed with different extension sets. A local user can trigger processing in which one clone installs a helper extension but remains unconfirmed, and another adds extensions for labels or NAT, invalidating a pointer in the expectation list, to cause access to freed memory during subsequent destruction.


Affected software

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-aws (Ubuntu package)
linux-gcp (Ubuntu package)
linux-oracle (Ubuntu package)
linux-ibm (Ubuntu package)
linux-hwe-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)

How to mitigate CVE-2026-98441

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - update to 7.0.0-42.42
linux-aws (Ubuntu package) - update to 7.0.0-1016.17
linux-gcp (Ubuntu package) - update to 7.0.0-1016.18
linux-oracle (Ubuntu package) - update to 7.0.0-1015.16
linux-ibm (Ubuntu package) - update to 7.0.0-1017.17
linux-hwe-7.0 (Ubuntu package) - update to 7.0.0-42.42~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1017.17

External References

Related Security Bulletins