SB20261029183 - Use-after-free in Linux kernel ipv4

Description

This security bulletin contains information about 1 vulnerability.

1) Use-after-free (CVE-ID: CVE-2026-99138)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 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]

The vulnerability allows a local user to potentially cause a denial of service by crashing the kernel.

The vulnerability exists due to use-after-free in do_tcp_getsockopt() when handling TCP_CC_INFO requests without protecting the congestion-control operations pointer against concurrent deallocation. A local user can request TCP congestion-control information while dynamically allocated BPF struct_ops congestion-control operations are being freed to trigger a stale pointer dereference or function-pointer call, potentially crashing the kernel.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/385e474086c2e7e29e2dded690be40dc273e20ee
• https://git.kernel.org/stable/c/39aa489e85752f9de214edb0f85e4d578e57af29
• https://git.kernel.org/stable/c/86814e5370068ec2bf0caa6e6d55c3e5bfc6c324