CVE-2026-90284

Description

In the Linux kernel, the following vulnerability has been resolved: firmware_loader: do not queue completed sysfs fallback requests fw_load_sysfs_fallback() calls device_add() before adding the fw_priv to pending_fw_head. device_add() publishes the fallback loading interface, so a userspace helper which discovers the device by scanning sysfs can write 0 to the loading attribute and complete the request before it is queued as pending. In that interleaving firmware_loading_store() calls fw_state_done() while pending_list still points to itself, so it cannot remove an entry from pending_fw_head. The subsequent unconditional list_add() then queues an already-completed fw_priv. Once the request is released, pending_fw_head can retain a pointer to freed memory and the next fallback request can fault while validating the list. Only in-flight fallback requests need suspend or reboot abort handling. If the request is already DONE after device_add(), return success from the fallback path without sending another uevent, waiting again, or queueing it as pending. This preserves the invariant that pending_fw_head contains only active fallback requests.

References

• https://git.kernel.org/stable/c/5a250bff75a446374c05622973b18b4ab662b504
• https://git.kernel.org/stable/c/6eaa632d0ed7bbb84f9cb670e5ec4e2cecf4cc7b
• https://git.kernel.org/stable/c/85aeb8fc61839098ae0942ccba86e669c08e75d4
• https://git.kernel.org/stable/c/93a2385730540105df8524447dcc11309ad280f9
• https://git.kernel.org/stable/c/b48373c901951fad1a26bd7c33ad91172b3945b5