CVE-2025-68336 locking/spinlock/debug: Fix data-race in do_raw_write_lock
A data race in the Linux kernel's spinlock debug code can lead to inconsistent state, potentially causing system instability or crashes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-68336?
CVE-2025-68336 is a high-severity vulnerability in Linux, published on 22 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
locking/spinlock/debug: Fix data-race in do_raw_write_lock
KCSAN reports:
BUG: KCSAN: data-race in do_raw_write_lock / do_raw_write_lock
write (marked) to 0xffff800009cf504c of 4 bytes by task 1102 on cpu 1: do_raw_write_lock+0x120/0x204 _raw_write_lock_irq do_exit call_usermodehelper_exec_async ret_from_fork
read to 0xffff800009cf504c of 4 bytes by task 1103 on cpu 0: do_raw_write_lock+0x88/0x204 _raw_write_lock_irq do_exit call_usermodehelper_exec_async ret_from_fork
value changed: 0xffffffff -> 0x00000001
Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 1103 Comm: kworker/u4:1 6.1.111
Commit 1a365e822372 ("locking/spinlock/debug: Fix various data races") has adressed most of these races, but seems to be not consistent/not complete.
>From do_raw_write_lock() only debug_write_lock_after() part has been converted to WRITE_ONCE(), but not debug_write_lock_before() part. Do it now.
Which versions are affected by CVE-2025-68336?
How do I fix CVE-2025-68336?
Apply the vendor's patch.
Is CVE-2025-68336 being exploited?
There is no known exploitation of CVE-2025-68336 in the wild and no public exploit code.
Sources
Also known as AZL-72889, BELL-CVE-2025-68336, DEBIAN-CVE-2025-68336, GHSA-hrvw-g8xf-vhvj, ROOT-OS-DEBIAN-11-CVE-2025-68336, ROOT-OS-DEBIAN-12-CVE-2025-68336 and 3 more.