CVE-2023-53698 xsk: fix refcount underflow in error path
A refcount underflow in the Linux kernel XSK subsystem can cause a denial of service when memory allocation fails during socket setup.
- 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-2023-53698?
CVE-2023-53698 is a high-severity vulnerability in Linux, published on 22 Oct 2025. 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:
xsk: fix refcount underflow in error path
Fix a refcount underflow problem reported by syzbot that can happen when a system is running out of memory. If xp_alloc_tx_descs() fails, and it can only fail due to not having enough memory, then the error path is triggered. In this error path, the refcount of the pool is decremented as it has incremented before. However, the reference to the pool in the socket was not nulled. This means that when the socket is closed later, the socket teardown logic will think that there is a pool attached to the socket and try to decrease the refcount again, leading to a refcount underflow.
I chose this fix as it involved adding just a single line. Another option would have been to move xp_get_pool() and the assignment of xs->pool to after the if-statement and using xs_umem->pool instead of xs->pool in the whole if-statement resulting in somewhat simpler code, but this would have led to much more churn in the code base perhaps making it harder to backport.
Which versions are affected by CVE-2023-53698?
How do I fix CVE-2023-53698?
Apply the vendor's patch.
Is CVE-2023-53698 being exploited?
There is no known exploitation of CVE-2023-53698 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2023-53698, DEBIAN-CVE-2023-53698, GHSA-f7vc-g3xh-9xx2, UBUNTU-CVE-2023-53698.