Use-after-free in Linux kernel - CVE-2026-80849

Vulnerability identifier: #VU147072

CSH Severity: Low

CVSS v4: 0 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-80849

CWE-ID: CWE-416

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to access freed memory.

The vulnerability exists due to use-after-free in current_key handling in the TCP Authentication Option (TCP-AO) code when processing inbound TCP-AO traffic during a socket reconnect to a different peer. A local user can race inbound TCP-AO processing with reconnecting a socket to another peer to access freed memory.

Linux kernel
Debian Linux
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)
linux (Debian package)

Install security update from vendor's repository.

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
linux (Debian package) - update to 6.12.111-1

• https://git.kernel.org/stable/c/2857dcbd03cf3354af0fba1b65c6a260fb43811a
• https://git.kernel.org/stable/c/73fde8fe4469f4ed8f0afcc0b9d6413002a9e6b3
• https://git.kernel.org/stable/c/84a93b4e012587d0a4a84ffb23ec6da18e9d85f9
• https://git.kernel.org/stable/c/da4471557f279d0f56605158a625bb6e49ef7d41
• https://git.kernel.org/stable/c/e54ad693eddb40c595add013f545354c538e325b

• Use-after-free in Linux kernel ipv4
• Debian update for linux
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more