Use-after-free in Linux kernel - CVE-2026-64523

Vulnerability identifier: #VU139413

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-2026-64523

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 in handshake_req_submit() and the net/handshake request handling code when processing a pending handshake request while the associated socket file is released concurrently. A local user can trigger a race involving socket teardown and handshake submission to cause a denial of service.

The issue arises because a socket reference alone does not keep the backing struct socket alive, and a concurrent cancellation or completion path can race request cleanup.

Linux kernel
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
Ubuntu
kernel (Red Hat package)
linux-nvidia-tegra (Ubuntu package)
linux-aws (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel (Red Hat package) - update to 6.12.0-211.69.1.el10_2
linux-nvidia-tegra (Ubuntu package) - update to 6.8.0-1035.38
linux-aws (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1015.15
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-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1
linux-nvidia (Ubuntu package) - addressed in versions 7.0.0-1016.16~24.04.1, 7.0.0-1016.16
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

• https://git.kernel.org/stable/c/09dba37eee70d0596e26645015f1aa95a9848e9d
• https://git.kernel.org/stable/c/16eaba5aa89c04eea125905bb8f988c1897f4f29
• https://git.kernel.org/stable/c/685b10dd0e32c7782cead16c8cf055c609678583

• Use-after-free in Linux kernel handshake
• Ubuntu update for linux-aws
• Ubuntu update for linux-nvidia-bos
• Ubuntu update for linux-nvidia
• Ubuntu update for linux-gcp-7.0
• Ubuntu update for linux-oracle-7.0
• Ubuntu update for linux-azure-7.0
• Ubuntu update for linux-nvidia-tegra
• Red Hat Enterprise Linux 10 update for kernel