CVE-2026-89524 wifi: ath6kl: clamp assoc request/response lengths before subtracting IE offsets
An integer underflow in the ath6kl WiFi driver allows attackers to disclose adjacent kernel memory to user space via crafted association events.
- 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-2026-89524?
CVE-2026-89524 is a high-severity vulnerability in Linux, published on 11 Sep 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: ath6kl: clamp assoc request/response lengths before subtracting IE offsets
ath6kl_cfg80211_connect_event() subtracts fixed IE offsets from assoc_req_len (-= 4) and assoc_resp_len (-= 6), both u8, with no lower bound. The aggregate check recently added to ath6kl_wmi_connect_event_rx() bounds the declared lengths from above (their sum must fit the received event), but an assoc request/response shorter than its fixed offset still underflows here: the u8 wraps to ~250, and cfg80211_connect_result() / cfg80211_roamed() then treat that wrapped value as the IE length and copy that many bytes out of the small assoc_info buffer to user space via nl80211, disclosing adjacent slab memory.
Clamp both lengths to their offsets before subtracting.
Found by 0sec (https://0sec.ai) using automated source analysis; the missing lower bound is evident from source. Compile-tested.
Which versions are affected by CVE-2026-89524?
How do I fix CVE-2026-89524?
Apply the vendor's patch.
Is CVE-2026-89524 being exploited?
There is no known exploitation of CVE-2026-89524 in the wild and no public exploit code.
Sources
Also known as AZL-100587, BELL-CVE-2026-89524, DEBIAN-CVE-2026-89524, GHSA-5r7p-vjpr-vvgf, UBUNTU-CVE-2026-89524.