Out-of-bounds write in Linux kernel - CVE-2026-74554

Vulnerability identifier: #VU143233

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-2026-74554

CWE-ID: CWE-787

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 an out-of-bounds write in ath12k_mac_dp_peer_cleanup() when cleaning up MLO peers. A local user can trigger peer cleanup with a crafted peer_id value carrying the ATH12K_PEER_ML_ID_VALID bit to cause a denial of service.

The issue affects the ML peer ID bitmap handling and can corrupt memory adjacent to ah->free_ml_peer_id_map; the intended bitmap entry is also not cleared, which can exhaust available IDs for subsequent allocations.

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/234b5cb81e6fcc1e3b31b13deff66130be55f36e
• https://git.kernel.org/stable/c/47abd2ca281531deee38a3b3770d885e270e9fc9

• Out-of-bounds write in Linux kernel ath ath12k driver
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more