Use-after-free in Linux kernel - CVE-2026-72139

Vulnerability identifier: #VU143452

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-2026-72139

CWE-ID: CWE-416

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 use-after-free in tcp_connect() and tcp_clear_md5_list() when reconciling TCP MD5 and TCP-AO authentication state during connection setup. A local user can trigger concurrent socket operations that race with RCU readers to cause a denial of service.

The race occurs while the socket is in TCP_SYN_SENT and already present in the inet ehash, where softirq RX-path readers may access the authentication data through RCU-protected lookups.

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/33a1bee413628378fd036a4f2b17ba86b0bc560c
• https://git.kernel.org/stable/c/b74cd55038905d5e74c1de109ab78a30b2ea0e1f
• https://git.kernel.org/stable/c/da48b9bf1eb95a9cfd09d615ca58cfc2b03de369

• Use-after-free in Linux kernel ipv4
• 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