CVE-2026-74554 wifi: ath12k: fix out-of-bounds clear_bit in ath12k_mac_dp_peer_cleanup()
An out-of-bounds write in the ath12k WiFi driver corrupts memory, potentially causing denial of service or code execution in the Linux kernel.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74554?
CVE-2026-74554 is a high-severity memory corruption vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
wifi: ath12k: fix out-of-bounds clear_bit in ath12k_mac_dp_peer_cleanup()
ath12k_mac_dp_peer_cleanup() clears the ML peer ID slot on the free_ml_peer_id_map bitmap by indexing it with dp_peer->peer_id. That is wrong: dp_peer->peer_id for an MLO peer always carries the ATH12K_PEER_ML_ID_VALID bit (BIT(13)), so clear_bit() is invoked with index >= 0x2000, which is far outside the bitmap of ATH12K_MAX_MLO_PEERS (256) bits and corrupts memory adjacent to ah->free_ml_peer_id_map. The intended bitmap entry also never gets cleared, so subsequent ath12k_peer_ml_alloc() calls eventually run out of IDs.
The ID without the VALID bit is what ath12k_peer_ml_alloc() returned and is stored in ahsta->ml_peer_id. Use that instead.
While there, also reset ahsta->ml_peer_id to ATH12K_MLO_PEER_ID_INVALID so the bitmap and ahsta->ml_peer_id stay in sync.
Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c5-00302-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.115823.3
Which versions are affected by CVE-2026-74554?
How do I fix CVE-2026-74554?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-74554 being exploited?
There is no known exploitation of CVE-2026-74554 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-74554, GHSA-m2x9-5x38-cjm5, UBUNTU-CVE-2026-74554.