CVE-2025-21669 vsock/virtio: discard packets if the transport changes
A NULL pointer dereference in the Linux kernel vsock/virtio module allows local attackers to cause a system crash by triggering specific socket transport changes.
- 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-2025-21669?
CVE-2025-21669 is a high-severity vulnerability in Linux kernel, published on 31 Jan 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:
vsock/virtio: discard packets if the transport changes
If the socket has been de-assigned or assigned to another transport, we must discard any packets received because they are not expected and would cause issues when we access vsk->transport.
A possible scenario is described by Hyunwoo Kim in the attached link, where after a first connect() interrupted by a signal, and a second connect() failed, we can find `vsk->transport` at NULL, leading to a NULL pointer dereference.
Weakness: CWE-476
Which versions are affected by CVE-2025-21669?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-21669?
Apply the vendor's patch.
Is CVE-2025-21669 being exploited?
There is no known exploitation of CVE-2025-21669 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-56393, AZL-56411, BELL-CVE-2025-21669, DEBIAN-CVE-2025-21669, GHSA-7hhm-hgmx-pp76, UBUNTU-CVE-2025-21669.