Always-Incorrect Control Flow Implementation in Linux kernel - CVE-2026-72418

Vulnerability identifier: #VU143023

CSH Severity: Medium

CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-72418

CWE-ID: CWE-670

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 state handling in nf_conncount when processing early-confirmed connection tracking entries for reused TIME_WAIT sockets or similar setup packets. A remote attacker can initiate network connections that trigger miscounting to cause a denial of service.

The issue can cause valid new connections to be falsely rejected in connlimit soft-limiting scenarios.

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/000ac6830b56499d6b65fd91486ce6689eb02be4
• https://git.kernel.org/stable/c/329f2626ee5cb8fafdf6b58b624311529c57cb45
• https://git.kernel.org/stable/c/3793d24de224943e0a6016bbeffb6f5c4cea2e3d
• https://git.kernel.org/stable/c/abef7f817217fcb62c11821d6b895063eadb2828
• https://git.kernel.org/stable/c/be52572c6d55f677ba76869d3c63805c0d4891a3
• https://git.kernel.org/stable/c/c8b6f36f766991e3ebebec6596daee4b04dcbc49
• https://git.kernel.org/stable/c/cbe2d14a7c5b1fc71821fbfee5c4963917411e92
• https://git.kernel.org/stable/c/ebfe8249ba79e4ff0f1e3aad8787b992ef27f026

• Always-Incorrect Control Flow Implementation 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