CVE-2026-89501 ring-buffer: Hold cpu_buffer::lock when resizing a subbuf
A race condition in the Linux kernel ring buffer allows attackers to cause a denial of service by triggering concurrent subbuffer resizing and page allocation.
- 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-2026-89501?
CVE-2026-89501 is a high-severity 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:
ring-buffer: Hold cpu_buffer::lock when resizing a subbuf
Because, ring_buffer_subbuf_order_set() can clear cpu_buffer->free_page, hold cpu_buffer->lock to prevent races with ring_buffer_alloc_read_page() and ring_buffer_free_read_page().
Which versions are affected by CVE-2026-89501?
How do I fix CVE-2026-89501?
Apply the vendor's patch.
Is CVE-2026-89501 being exploited?
There is no known exploitation of CVE-2026-89501 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-89501, DEBIAN-CVE-2026-89501, GHSA-9677-q555-56wx, UBUNTU-CVE-2026-89501.