CVE-2026-80991 net: ravb: serialize PTP clock teardown
A race condition in the Linux kernel's ravb network driver allows a use-after-free of the PTP clock, potentially leading to code execution or system crashes.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-80991?
CVE-2026-80991 is a high-severity use after free vulnerability in Linux, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
net: ravb: serialize PTP clock teardown
ravb_ptp_interrupt() can race with ravb_ptp_stop() and pass the clock to ptp_clock_event() while ptp_clock_unregister() is freeing it. This can lead to a use-after-free.
Use READ_ONCE() and WRITE_ONCE() for lockless access to the clock pointer. Atomically detach it with xchg() before disabling PTP interrupts, then synchronize all IRQs which can invoke ravb_ptp_interrupt() before unregistering the detached clock.
A handler which read the old pointer completes before the clock is unregistered, while later handlers read NULL and skip the event.
Which versions are affected by CVE-2026-80991?
How do I fix CVE-2026-80991?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-80991 being exploited?
There is no known exploitation of CVE-2026-80991 in the wild and no public exploit code.
Sources
Also known as AZL-100130, BELL-CVE-2026-80991, DEBIAN-CVE-2026-80991, GHSA-h2g3-mgp6-wj27, UBUNTU-CVE-2026-80991.