CVE-2026-80944: wifi: mwifiex: Detach sync cmd buffer on interrupted wait
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 cmdnode->databuf. Several callers pass stack-allocated objects there.
If waiteventinterruptibletimeout() 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 cmdnode->databuf 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:
cmdwaitq terminated: -512 Unable to handle kernel paging request at virtual address 002c583837384662 Kernel panic - not syncing: stack-protector: Kernel stack is corrupted ... Tainted: [M]=MACHINECHECK
The fault address decodes as little-endian ASCII:
0x002c583837384662 -> "bF878X,\0"
which is a fragment of the VERSIONEXT 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 VERSIONEXT string. This points at a late VERSIONEXT response writing through a stale stack-backed databuf 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.
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
wifi: mwifiexto a version that resolves this vulnerability.Fixed in 16.92.21.p153.7 - Configuration
Apply the fix described as “Detach sync cmd buffer on interrupted wait” so that the sync command’s caller-owned data buffer is detached from cmd_node->data_buf when wait_event_interruptible_timeout() is interrupted, preventing response writing through stale stack-backed data_buf/corrupted stack control data.
wifi: mwifiex Detach sync cmd buffer on interrupted wait = enabled
Event History
Frequently Asked Questions
What conditions are needed to trigger the corruption?
The system must issue an mwifiex synchronous firmware command whose caller-provided buffer is retained in cmd_node->data_buf, and the interruptible command wait must be interrupted before the firmware response arrives. A later firmware response can then copy data into the caller's released stack buffer.
Which activity was observed to expose the issue?
The reported stack corruption occurred during repeated Wi-Fi association and disassociation cycles. The triggering command wait was interrupted immediately before the invalid pointer dereference.
How might an affected system present?
The reported outcome was a kernel paging-request fault followed by a stack-protector corruption panic. Logs may show "cmd_wait_q terminated: -512" before the fault.