published December 18, 2025
In the Linux kernel, the following vulnerability has been resolved:
scsi: imm: Fix use-after-free bug caused by unfinished delayed work
The delayed work item 'imm_tq' is initialized in imm_attach() and
scheduled via imm_queuecommand() for processing SCSI commands. When the
IMM parallel port SCSI host adapter is detached through imm_detach(),
the imm_struct device instance is deallocated.
However, the delayed work might still be pending or executing
when imm_detach() is called, leading to use-after-free bugs
when the work function imm_interrupt() accesses the already
freed imm_struct memory.
The race condition can occur as follows:
CPU 0(detach thread) | CPU 1
| imm_queuecommand()
| imm_queuecommand_lck()
imm_detach() | schedule_delayed_work()
kfree(dev) //FREE | imm_interrupt()
| dev = container_of(...) //USE
dev-> //USE
Add disable_delayed_work_sync() in imm_detach() to guarantee proper
cancellation of the delayed work item before imm_struct is deallocated.