CVE-2025-21800 net/mlx5: HWS, fix definer's HWS_SET32 macro for negative offset
A negative bit offset in the mlx5 HWS definer macro causes a shift-out-of-bounds error, potentially leading to a kernel crash or denial of service.
- 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-2025-21800?
CVE-2025-21800 is a high-severity vulnerability in Linux kernel, published on 27 Feb 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:
net/mlx5: HWS, fix definer's HWS_SET32 macro for negative offset
When bit offset for HWS_SET32 macro is negative, UBSAN complains about the shift-out-of-bounds:
UBSAN: shift-out-of-bounds in drivers/net/ethernet/mellanox/mlx5/core/steering/hws/definer.c:177:2 shift exponent -8 is negative
Which versions are affected by CVE-2025-21800?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-21800?
Apply the vendor's patch.
Is CVE-2025-21800 being exploited?
There is no known exploitation of CVE-2025-21800 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-21800, DEBIAN-CVE-2025-21800, GHSA-5r9q-cj6r-c6jj, UBUNTU-CVE-2025-21800.