Use-after-free in Linux kernel - CVE-2026-99138
Published: October 29, 2026
Vulnerability identifier: #VU158458
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-2026-99138
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
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.
Affected software
Linux kernel
Debian Linux
linux (Debian package)
Debian Linux
linux (Debian package)
How to mitigate CVE-2026-99138
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3
linux (Debian package) - update to 6.12.115-2
linux (Debian package) - update to 6.12.115-2