Use-after-free in Linux kernel - CVE-2026-64045

Vulnerability identifier: #VU138606

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-2026-64045

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 ovpn_tcp_close() in the OpenVPN TCP transport handling code when closing a TCP socket concurrently with peer removal. A local user can trigger peer removal while closing the TCP file descriptor to cause a denial of service.

The issue occurs because a peer pointer obtained during an RCU read-side critical section is used after that section has ended.

Linux kernel
Ubuntu
linux-ibm (Ubuntu package)
linux-azure (Ubuntu package)
linux-aws (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
linux-ibm (Ubuntu package) - addressed in versions 7.0.0-1008.8, 7.0.0-1010.10
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1010.10
linux-aws (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1015.15
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

• https://git.kernel.org/stable/c/775d8d7ad02aa345e1588424a6a8b9ae49fb9012
• https://git.kernel.org/stable/c/d3ef441907fca7c340979e577a3db3bb634bf166
• https://git.kernel.org/stable/c/e5460eb7238c19d651a9b22b2378b587033a4095

• Use-after-free in Linux kernel net ovpn driver
• Ubuntu update for linux-ibm
• Ubuntu update for linux-azure
• Ubuntu update for linux-aws
• Ubuntu update for linux-nvidia-bos
• Ubuntu update for linux-nvidia