Improper input validation in Linux kernel - CVE-2026-72347

Vulnerability identifier: #VU143085

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-2026-72347

CWE-ID: CWE-20

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 input validation in the xt_connmark CONNMARK target revision 2 handling when evaluating a rule with invalid shift parameters. A local user can install a malformed rule with a shift_bits value of 32 or more or an invalid shift_dir value to cause a denial of service.

The issue is triggered when the malformed rule is evaluated in the packet path.

Linux kernel
Ubuntu
linux-nvidia (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)
linux-azure (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux-nvidia (Ubuntu package) - addressed in versions 5.15.0-1112.113, 5.15.0.1112.112
linux-nvidia-tegra (Ubuntu package) - update to 6.8.0-1036.39+1
linux-gcp-7.0 (Ubuntu package) - addressed in versions 7.0.0-38.38~24.04.4, 7.0.0-1013.13~24.04.1, 7.0.0-1014.14~24.04.1
linux (Ubuntu package) - addressed in versions 7.0.0-38.38, 7.0.0-38.38.1, 7.0.0-1008.9, 7.0.0-1013.13~24.04.1, 7.0.0-1014.14, 7.0.0-1015.15
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1015.15
linux-azure-7.0 (Ubuntu package) - addressed in versions 7.0.0-1016.16~24.04.1, 7.0.0-1017.17~24.04.1
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1016.16, 7.0.0-1017.17

• https://git.kernel.org/stable/c/1b47026fb4b35bac850ad6e8a4ad7fc018e09ebc
• https://git.kernel.org/stable/c/230173cc6105bdfb2696d37e6e56687b003fbe63
• https://git.kernel.org/stable/c/4eef84b09a3836919360c4232b0f16651a155eec
• https://git.kernel.org/stable/c/8ace320ac4416f5e5fbcd065309fb2dfcce787b0
• https://git.kernel.org/stable/c/9657bb11a6376ab0a79f05d433713d6944111e9d
• https://git.kernel.org/stable/c/c3fa852d117b3fda72265e4230e3967db4a74fcf
• https://git.kernel.org/stable/c/d8ce63d928b457fba7ed1e302492dfd32293671c

• Improper input validation in Linux kernel netfilter
• Ubuntu update for linux-gcp-7.0
• Ubuntu update for linux-nvidia
• Ubuntu update for linux-azure-7.0
• Ubuntu update for linux-nvidia-tegra
• Ubuntu update for linux
• Ubuntu update for linux-azure
• Ubuntu update for linux-oem-7.0