CVE-2026-80730 ring-buffer: Fix crash passing ERR_PTR to kthread_stop()
A kernel crash occurs during ring-buffer self-tests when error pointers are mishandled, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Not stated
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-80730?
CVE-2026-80730 is a vulnerability in Linux, published on 3 Sep 2026.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ring-buffer: Fix crash passing ERR_PTR to kthread_stop()
In test_ringbuffer()'s out_free cleanup loop, the check `!rb_threads[cpu]` only catches NULL entries and misses entries that hold an ERR_PTR.
rb_threads[] is static, so unassigned slots are NULL. But when kthread_run_on_cpu() fails for a cpu, it stores ERR_PTR(-ENOMEM) (or -EINTR) in rb_threads[cpu] before the creation loop jumps to out_free. That entry is non-NULL, so the old `!ptr` check does not break, and the cleanup proceeds to call kthread_stop() on the ERR_PTR. kthread_stop() then dereferences the bogus pointer, crashing the kernel during the late_initcall self-test.
crash logs: BUG: kernel NULL pointer dereference, address: 000000000000001c Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 1 Comm: swapper/0 Not tainted 7.2.0-rc6-dirty #7 PREEMPT(lazy) RIP: 0010:kthread_stop+0x2e/0x220 RBX: fffffffffffffff4 CR2: 000000000000001c Call Trace: <TASK> test_ringbuffer+0x1ec/0x650 do_one_initcall+0x6c/0x2c0 kernel_init_freeable+0x21d/0x420 kernel_init+0x15/0x1c0 ret_from_fork+0x21b/0x320 </TASK> Kernel panic - not syncing: Fatal exception
Which versions are affected by CVE-2026-80730?
How do I fix CVE-2026-80730?
Apply the vendor's patch.
Is CVE-2026-80730 being exploited?
There is no known exploitation of CVE-2026-80730 in the wild and no public exploit code.
Sources
Also known as AZL-99051, BELL-CVE-2026-80730, DEBIAN-CVE-2026-80730, GHSA-p8f7-pqwj-r94v, UBUNTU-CVE-2026-80730.