CVE-2025-40056 vhost: vringh: Fix copy_to_iter return value check
A flaw in the Linux kernel vhost vringh component allows attackers to cause memory corruption or denial of service due to improper return value checking.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-40056?
CVE-2025-40056 is a memory corruption vulnerability in Linux, published on 28 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:
vhost: vringh: Fix copy_to_iter return value check
The return value of copy_to_iter can't be negative, check whether the copied length is equal to the requested length instead of checking for negative values.
Which versions are affected by CVE-2025-40056?
How do I fix CVE-2025-40056?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2025-40056 being exploited?
There is no known exploitation of CVE-2025-40056 in the wild and no public exploit code.
Sources
Also known as AZL-68867, BELL-CVE-2025-40056, DEBIAN-CVE-2025-40056, GHSA-qqfp-3f8f-fv6r, ROOT-OS-DEBIAN-12-CVE-2025-40056, ROOT-OS-DEBIAN-13-CVE-2025-40056 and 2 more.