CVE-2026-90366 wifi: mt76: mt7996: reserve space for the CSA-abort countdown TLV
A buffer overflow in the mt7996 WiFi driver can cause a kernel panic via crafted beacon updates, requiring local or adjacent access.
- 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-2026-90366?
CVE-2026-90366 is a denial of service vulnerability in Linux, published on 17 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: mt76: mt7996: reserve space for the CSA-abort countdown TLV
When a CSA countdown is active, mt7996_mcu_beacon_cntdwn() emits two bss_bcn_cntdwn_tlv entries (the CSA countdown and the CCA-abort BCC), but MT7996_BEACON_UPDATE_SIZE only reserved one. With MBSSID enabled and a near-maximum beacon template the extra 8 bytes could push the offload command past MT7996_MAX_BSS_OFFLOAD_SIZE and trigger skb_over_panic(). Reserve room for both countdown TLVs.
Which versions are affected by CVE-2026-90366?
How do I fix CVE-2026-90366?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-90366 being exploited?
There is no known exploitation of CVE-2026-90366 in the wild and no public exploit code.
Sources
Also known as AZL-102923, BELL-CVE-2026-90366, DEBIAN-CVE-2026-90366, GHSA-9rj4-wjx5-8xc6, UBUNTU-CVE-2026-90366.