Use-after-free in Linux kernel - CVE-2026-53260

Vulnerability identifier: #VU135500

CSH Severity: Low

CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-53260

CWE-ID: CWE-416

Exploitation vector: Local access

Exploit availability: No public exploit available

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

The vulnerability exists due to a use-after-free race condition in reqsk_queue_hash_req() in net/ipv4/inet_connection_sock.c when handling TCP request socket timer setup and reference count initialization on PREEMPT_RT systems. A local user can trigger the race to cause a denial of service.

Exploitation requires a PREEMPT_RT-enabled kernel.

Linux kernel
Debian Linux
Ubuntu
linux (Debian package)
linux (Ubuntu package)
linux-hwe-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-aws-7.0 (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Debian package) - update to 6.12.100-1
linux (Ubuntu package) - addressed in versions 7.0.0-29.29, 7.0.0-29.29.1, 7.0.0-1009.9, 7.0.0-1010.10, 7.0.0-1011.11, 7.0.0-1016.16
linux-hwe-7.0 (Ubuntu package) - update to 7.0.0-29.29~24.04.2
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1010.10
linux-aws-7.0 (Ubuntu package) - update to 7.0.0-1010.10~24.04.1

• https://git.kernel.org/stable/c/b183215ff714efb747d9d5a429322ba6404b5401
• https://git.kernel.org/stable/c/e10902df24488ca722303133acfc82490f7d59ad

• Use-after-free in Linux kernel ipv4
• Debian update for linux
• Ubuntu update for linux
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux-aws-7.0
• Ubuntu update for linux-hwe-7.0