Resource exhaustion in Linux kernel - CVE-2026-63834

Vulnerability identifier: #VU138825

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-2026-63834

CWE-ID: CWE-400

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 uncontrolled resource consumption in the batman-adv tp_meter unacked_list handling when processing crafted messages with small lengths and seqno gaps. A remote attacker can send specially crafted messages to cause a denial of service.

The issue can lead to an out-of-memory condition or excessive CPU usage from management overhead while searching the enlarged list.

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

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - addressed in versions 7.0.0-31.31, 7.0.0-31.31.1, 7.0.0-31.31~24.04.1, 7.0.0-1006.7, 7.0.0-1011.11~24.04.1, 7.0.0-1012.12, 7.0.0-1012.12~24.04.1
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1011.11, 7.0.0-1014.14
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oracle-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1013.13
linux-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1

• https://git.kernel.org/stable/c/1111a3381bca2d1f084a07686bc783af5ab23df7
• https://git.kernel.org/stable/c/1c616b0be4bd8399d485e25e91859373b95d6013
• https://git.kernel.org/stable/c/1fb8762600a393d1caccd63be5d07e1756982d68
• https://git.kernel.org/stable/c/2233787658db859f0a9b83cb397cf783bb8be865
• https://git.kernel.org/stable/c/31a88792bfba142be3c9521538c1db805677381f
• https://git.kernel.org/stable/c/c6231d628d06d841bc1617b2f7034f5f39876b16
• https://git.kernel.org/stable/c/e7c775110e1858e5a7471a23a9c9658c0af9df89
• https://git.kernel.org/stable/c/f8c499fd275e59203b77fca76ae6ef2d096c2133

• Resource exhaustion in Linux kernel batman-adv
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux
• Ubuntu update for linux-gcp-7.0
• Ubuntu update for linux-oracle-7.0
• Ubuntu update for linux-azure
• Ubuntu update for linux-azure-7.0