CVE-2026-68326: wifi: mwifiex: bound uAP association event IEs to the event buffer

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

wifi: mwifiex: bound uAP association event IEs to the event buffer

mwifiexprocessuapevent() handles EVENTUAPSTAASSOC by exposing the (re)association request IEs that the firmware copies into the event:

sinfo->assocreqies = &event->data[len]; len = (u8 )sinfo->assocreqies - (u8 )&event->framecontrol; sinfo->assocreqieslen = le16tocpu(event->len) - (u16)len;

event->len is supplied by the device firmware and is never validated, and the subtraction is unchecked. assocreqies points into adapter->eventbody[MAXEVENTSIZE], a fixed-size array embedded in the kmalloc()'d struct mwifiexadapter.

On the ap11nenabled path mwifiexsetstahtcap() walks these IEs with cfg80211findie(), whose foreachelement() loop dereferences each element header. A firmware-reported event->len larger than the bytes actually received makes assocreqieslen describe IEs that extend past eventbody, so the walk reads out of the adapter slab object, a slab-out-of-bounds read (KASAN: slab-out-of-bounds in cfg80211findie). An event->len smaller than the header instead makes the int subtraction negative, which wraps to a huge sizet when stored in assocreqieslen. The same length is handed to cfg80211newsta(), so a more modest over-claim can also copy stale eventbody bytes into the NL80211CMDNEWSTATION notification.

A malicious or malfunctioning mwifiex device (USB/SDIO/PCIe) can deliver such an event while the interface is in AP/uAP mode.

Validate event->len before use: reject a length that underflows the header or that would place the IEs outside the eventbody[] buffer the event was copied into. event->len here is struct mwifiexassocevent.len, a payload field internal to this event, not the transport frame length, so it is validated in this handler rather than at the generic MWIFIEXTYPEEVENT receive path, which only sees the event cause and the transport frame length. The bound is against eventbody[MAXEVENTSIZE] rather than the actually-received length because the transports store the event differently (USB and SDIO leave the 4-byte event header in eventskb, PCIe strips it via skbpull), whereas eventbody is the single fixed buffer all of them copy the event into. This is the event-path analogue of the receive-path bounds checks added in commit 119585281617 ("wifi: mwifiex: Fix OOB and integer underflow when rx packets").