CVE-2023-53205 KVM: s390/diag: fix racy access of physical cpu number in diag 9c handler
A race condition in the Linux kernel's KVM s390 diag handler allows out-of-bounds memory access, potentially leading to code execution or privilege escalation.
- 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-2023-53205?
CVE-2023-53205 is a high-severity vulnerability in Linux kernel, published on 15 Sep 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:
KVM: s390/diag: fix racy access of physical cpu number in diag 9c handler
We do check for target CPU == -1, but this might change at the time we are going to use it. Hold the physical target CPU in a local variable to avoid out-of-bound accesses to the cpu arrays.
Weakness: CWE-787
Which versions are affected by CVE-2023-53205?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2023-53205?
Apply the vendor's patch.
Is CVE-2023-53205 being exploited?
There is no known exploitation of CVE-2023-53205 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2023-53205, DEBIAN-CVE-2023-53205, GHSA-9r2v-25mx-g9gj, UBUNTU-CVE-2023-53205.