CVE-2025-21903 mctp i3c: handle NULL header address
A null pointer dereference in the Linux kernel MCTP I3C driver can cause a system crash when handling packets without neighbor table entries.
- 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-2025-21903?
CVE-2025-21903 is a medium-severity vulnerability in Linux kernel, published on 1 Apr 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:
mctp i3c: handle NULL header address
daddr can be NULL if there is no neighbour table entry present, in that case the tx packet should be dropped.
saddr will usually be set by MCTP core, but check for NULL in case a packet is transmitted by a different protocol.
Which versions are affected by CVE-2025-21903?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-21903?
Apply the vendor's patch.
Is CVE-2025-21903 being exploited?
There is no known exploitation of CVE-2025-21903 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-21903, DEBIAN-CVE-2025-21903, GHSA-p5qx-8g2f-7jgh, ROOT-OS-UBUNTU-2404-CVE-2025-21903, UBUNTU-CVE-2025-21903.