Improper input validation in Linux kernel - CVE-2026-72442

Vulnerability identifier: #VU142991

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-2026-72442

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 nf_flow_ip6_tunnel_proto() in the netfilter flowtable IPv6 tunnel handling code when processing IPv6-in-IPv6 encapsulated packets. A remote attacker can send specially crafted IPv6 tunnel traffic to cause a denial of service.

The issue arises because the fast path does not handle IPv6 extension headers in this encapsulation case.

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-realtime (Ubuntu package)
linux-oracle (Ubuntu package)
linux-gcp (Ubuntu package)
linux-aws (Ubuntu package)
linux-raspi (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-ibm (Ubuntu package)
linux-nvidia-bos (Ubuntu package)
linux-hwe-7.0 (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-gke (Ubuntu package)
linux-aws-7.0 (Ubuntu package)
linux-nvidia-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 (Ubuntu package) - update to 7.0.0-34.34
linux-realtime (Ubuntu package) - update to 7.0.0-34.34.1
linux-oracle (Ubuntu package) - update to 7.0.0-1012.12
linux-gcp (Ubuntu package) - update to 7.0.0-1013.13
linux-aws (Ubuntu package) - update to 7.0.0-1013.13
linux-raspi (Ubuntu package) - update to 7.0.0-1020.20
linux-nvidia (Ubuntu package) - update to 7.0.0-1025.26
linux-ibm (Ubuntu package) - update to 7.0.0-1014.14
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2022.23
linux-hwe-7.0 (Ubuntu package) - update to 7.0.0-34.34~24.04.1
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1013.13~24.04.1
linux-oracle-7.0 (Ubuntu package) - update to 7.0.0-1012.12~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1014.14
linux-gke (Ubuntu package) - update to 7.0.0-1007.8
linux-aws-7.0 (Ubuntu package) - update to 7.0.0-1013.13~24.04.1
linux-nvidia-7.0 (Ubuntu package) - update to 7.0.0-1024.25~24.04.1
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/7f8d816a9aa2729d270418f00c9ef5e85bfc1b31
• https://git.kernel.org/stable/c/f4c2d8668d85ed125985da663c824a9c25498257

• Improper input validation in Linux kernel net netfilter
• Ubuntu update for linux-gcp
• Ubuntu update for linux
• Ubuntu update for linux-oracle-7.0
• Ubuntu update for linux-gke
• Ubuntu update for linux-azure-7.0
• Ubuntu update for linux-azure
• Ubuntu update for linux-nvidia-7.0, linux-nvidia-bos
• Ubuntu update for linux-nvidia