Improper input validation in Linux kernel - CVE-2026-64208

Vulnerability identifier: #VU139790

CSH Severity: Medium

CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-64208

CWE-ID: CWE-20

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper input validation in the AF_RXRPC RxGK packet handling and crypto/krb5 length-check logic when processing secured DATA packets. A remote attacker can send a specially crafted short packet to cause a denial of service.

Linux kernel
Ubuntu
linux-aws (Ubuntu package)
linux-gcp-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
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

• https://git.kernel.org/stable/c/2b50aceafe6606ea52ed42aadd1b4d44a188aade
• https://git.kernel.org/stable/c/585f9f6aef5c4542ac9d6ec45cd7dbc7df9af3ff
• https://git.kernel.org/stable/c/9217017f4bce53dddb8d547837f1f707045d64ad

• Improper input validation in Linux kernel rxrpc
• Ubuntu update for linux-aws
• Ubuntu update for linux-nvidia-bos
• Ubuntu update for linux-nvidia
• Ubuntu update for linux-gcp-7.0