CVE-2026-98184

In the Linux kernel, the following vulnerability has been resolved:

wifi: mwifiex: prevent authentication frame length truncation

mwifiex cfg80211 authenticate() derives the authentication frame length from req->ie len and req->auth data len, both of type size t, but stores it in a u16.

NL80211 ATTR AUTH DATA only has a minimum length policy. Since nla len is a u16, a single attribute can carry up to 65531 bytes of payload, so the sum can exceed U16 MAX before it is assigned to pkt len. The truncated pkt len determines the skb frame area, while the copy length remains req->auth data len - 4, resulting in a heap buffer overflow.

For example, with auth data len equal to 65510 and no IEs, the sum is 65546. It is truncated to 10 and then reduced by four to 6. The driver appends only six bytes to the skb with skb put(), but then copies 65506 user-provided bytes into the authentication body.

Reaching this path requires CAP NET ADMIN in the user namespace owning the network namespace, an up station netdev, and a suitable BSS/SAE authentication request.

Compute the length in size t, reject values that cannot be represented by the firmware's u16 frame length field, and only then assign it to pkt len.