Improper locking in Linux kernel - CVE-2026-98646

Vulnerability identifier: #VU156959

CSH Severity: Low

CVSS v4: 4.6 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-98646

CWE-ID: CWE-667

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local privileged user to trigger kernel warnings and potentially disrupt system stability.

The vulnerability exists due to improper locking in inet_csk_listen_stop() when stopping a TCP listener with children in its accept queue from a BPF TCP iterator. A local privileged user can invoke bpf_sock_destroy() through the iterator to reach cond_resched() while an RCU read-side lock is held, triggering an invalid-context warning and potentially disrupting system stability.

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-aws (Ubuntu package)
linux-gcp (Ubuntu package)
linux-oracle (Ubuntu package)
linux-ibm (Ubuntu package)
linux-hwe-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - update to 7.0.0-42.42
linux-aws (Ubuntu package) - update to 7.0.0-1016.17
linux-gcp (Ubuntu package) - update to 7.0.0-1016.18
linux-oracle (Ubuntu package) - update to 7.0.0-1015.16
linux-ibm (Ubuntu package) - update to 7.0.0-1017.17
linux-hwe-7.0 (Ubuntu package) - update to 7.0.0-42.42~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1017.17

• https://git.kernel.org/stable/c/23da88d1597ee7fdda373e1530284b763710911f
• https://git.kernel.org/stable/c/55bbebf2829c3f47c5a48fc261740301d0f25f48
• https://git.kernel.org/stable/c/5b52417c6196e05618a3b5d9753dbed9adef0166
• https://git.kernel.org/stable/c/eaab8cab451b9502ce224cd202550375b894a467
• https://git.kernel.org/stable/c/ee7246bccb9da66076dd8094daa48bdc761d6b76

• Improper locking in Linux kernel ipv4
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more