Incorrect calculation in Linux kernel - CVE-2026-72250

Vulnerability identifier: #VU143189

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-2026-72250

CWE-ID: CWE-682

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 an unset header offset in nf_ct_frag6_reasm() when processing IPv6 fragments on the NF_INET_LOCAL_OUT defragmentation path. A local user can send a specially crafted fragmented IPv6 packet to cause a denial of service.

The issue occurs because skb->mac_header may still hold the unset sentinel value when no link-layer header is present yet.

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/00bdce2fda7e430d24cfbc96764a1b96deb31f82
• https://git.kernel.org/stable/c/2a95ec21824a8ad81ad660b12231456fc0ac9830
• https://git.kernel.org/stable/c/3b08fed5b7e0d5e3a25d73ef3ba09cd33ade16c9
• https://git.kernel.org/stable/c/53ef70a315420ed31581d38343684b3bf9a3c76d
• https://git.kernel.org/stable/c/6e8cd710ca35c576f5f2e5a396047c9ac61f75e5
• https://git.kernel.org/stable/c/a58230f3a7c4f6c3261786bc1efb72c42e68cd25
• https://git.kernel.org/stable/c/bbcdef2061b170af45702ce6b359c02c12acfc94
• https://git.kernel.org/stable/c/cd0d7bbc027b4d3329712cdcdeb4e5567ffd0d58

• Incorrect calculation in Linux kernel ipv6 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