CVE-2026-80944

Summary

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

wifi: mwifiex: Detach sync cmd buffer on interrupted wait

mwifiex synchronous commands keep the caller-provided data buffer in cmd_node->data_buf. Several callers pass stack-allocated objects there.

If wait_event_interruptible_timeout() is interrupted, the caller can return and release that stack object while the firmware command is still the current command. A late firmware response then reaches the normal response handler, which can copy data through cmd_node->data_buf into the stale stack address.

This fixes a stack corruption observed during repeated association and disassociation cycles. The panic trace showed the command wait being interrupted immediately before a bad pointer dereference:

cmd_wait_q terminated: -512 Unable to handle kernel paging request at virtual address 002c583837384662 Kernel panic - not syncing: stack-protector: Kernel stack is corrupted … Tainted: [M]=MACHINE_CHECK

The fault address decodes as little-endian ASCII:

0x002c583837384662 -> "bF878X,\0"

which is a fragment of the VERSION_EXT firmware string exposed as debugfs "verext":

w8997o-V4, RF878X, FP92, 16.92.21.p153.7

The same runs also showed corrupted control data containing:

0x2400372e333531 -> "153.7\0$"

which is the tail of the same VERSION_EXT string. This points at a late VERSION_EXT response writing through a stale stack-backed data_buf after the interrupted wait returned.

After cancelling pending commands on an interrupted or timed-out wait, detach the caller-owned data buffer from the still-current command. This preserves the existing command cancellation behaviour while preventing a late response from writing through a pointer whose lifetime ended with the waiting caller.

Tested on an i.MX8MP board using an 88W8997.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/8c67b8c50286e0cb7f18d667e6a37a2ec6e08ff9
• https://git.kernel.org/stable/c/9024c7729eb523cf4f3a4203966d3a4aaabf030d
• https://git.kernel.org/stable/c/9e06c9c8a1f10c55d9bc5d139656d58795e64483
• https://git.kernel.org/stable/c/f2134d6ff30cd6e1bf63d6b0a5d8e0839f0168b3
• https://git.kernel.org/stable/c/20ee9c03f261bf6ac59331e2ca7b46b23646412a
• https://git.kernel.org/stable/c/b1bbeb8970eeb6c6bf3cd5314138103f7b69446d
• https://git.kernel.org/stable/c/d29a165588b6a0cf7a38db5cbd602aef7ef8c658
• https://git.kernel.org/stable/c/ef06882c7d8a7400b67d0d003b1008093dd589ed

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