Infinite loop in Linux kernel - CVE-2026-63969

Vulnerability identifier: #VU138689

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-2026-63969

CWE-ID: CWE-835

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 improper handling of a stale linked-list state in rt6_fill_node() when walking IPv6 route sibling entries during softirq-side processing. A local user can trigger route state changes to cause a CPU stall.

The issue can result in an infinite loop in the walker.

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/279853aec9f58d5cd723e6e5617c1c3337b30383
• https://git.kernel.org/stable/c/5e40de719ee76b8d96e2556ce36dbd3bd07bf37d
• https://git.kernel.org/stable/c/9f72412bcf60144f252b0d6205106abf14344abc
• https://git.kernel.org/stable/c/b014a63d2f2c2c767762b548381882dfb1655529
• https://git.kernel.org/stable/c/c65b1f60237daac7c56c2652e064cc566a45dc81
• https://git.kernel.org/stable/c/dc36a04621dcc2447dae428709207810b6c06e14

• Infinite loop in Linux kernel ipv6
• 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