Use-after-free in Linux kernel - CVE-2026-53349

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Main Vulnerability Database Vulnerabilities #VU136696

Use-after-free in Linux kernel - CVE-2026-53349

Published: July 2, 2026


Vulnerability identifier: #VU136696
CSH Severity: Low
CVSS v4: 5.6 [CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-53349
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

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

The vulnerability exists due to a use-after-free in netfilter nf_conntrack expectation handling when processing an expected connection after a NAT helper module has been unloaded. A local privileged user can unload a NAT helper module while live expectations remain and then trigger the expected connection to cause a denial of service.

Reaching the vulnerable state requires CAP_SYS_MODULE in the initial user namespace to remove a NAT helper that still has live expectations.


Affected software

Linux kernel
openEuler
Ubuntu
bpftool
kernel
python3-perf-debuginfo
python3-perf
perf-debuginfo
perf
kernel-tools-devel
kernel-tools-debuginfo
kernel-tools
kernel-source
kernel-headers
kernel-devel
kernel-debugsource
kernel-debuginfo
bpftool-debuginfo
linux (Ubuntu package)
linux-azure (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-ibm (Ubuntu package)
linux-azure-7.0 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-7.0 (Ubuntu package)
linux-raspi (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

How to mitigate CVE-2026-53349

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
bpftool - update to 6.6.0-145.1.20.157
kernel - update to 6.6.0-145.1.20.157
python3-perf-debuginfo - update to 6.6.0-145.1.20.157
python3-perf - update to 6.6.0-145.1.20.157
perf-debuginfo - update to 6.6.0-145.1.20.157
perf - update to 6.6.0-145.1.20.157
kernel-tools-devel - update to 6.6.0-145.1.20.157
kernel-tools-debuginfo - update to 6.6.0-145.1.20.157
kernel-tools - update to 6.6.0-145.1.20.157
kernel-source - update to 6.6.0-145.1.20.157
kernel-headers - update to 6.6.0-145.1.20.157
kernel-devel - update to 6.6.0-145.1.20.157
kernel-debugsource - update to 6.6.0-145.1.20.157
kernel-debuginfo - update to 6.6.0-145.1.20.157
bpftool-debuginfo - update to 6.6.0-145.1.20.157
linux (Ubuntu package) - addressed in versions 7.0.0-31.31, 7.0.0-31.31.1, 7.0.0-31.31~24.04.1, 7.0.0-1006.7, 7.0.0-1011.11~24.04.1, 7.0.0-1012.12, 7.0.0-1012.12~24.04.1
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1011.11, 7.0.0-1014.14
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oracle-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1013.13
linux-ibm (Ubuntu package) - update to 7.0.0-1013.13
linux-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1
linux-nvidia (Ubuntu package) - update to 7.0.0-1018.18
linux-nvidia-7.0 (Ubuntu package) - update to 7.0.0-1018.18~24.04.1
linux-raspi (Ubuntu package) - update to 7.0.0-1019.19
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2018.18

External References

Related Security Bulletins