Use-after-free in Linux kernel - CVE-2026-64523
Published: July 27, 2026
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
Vulnerability details
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.
Affected software
Linux kernel
Ubuntu
linux-aws (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)
Ubuntu
linux-aws (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)
How to mitigate CVE-2026-64523
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3
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-nvidia (Ubuntu package) - addressed in versions 7.0.0-1016.16, 7.0.0-1016.16~24.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16
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-nvidia (Ubuntu package) - addressed in versions 7.0.0-1016.16, 7.0.0-1016.16~24.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16