CVE-2025-5555 Nixdorf Wincor PORT IO Driver IOCTL wnport.sys sub_11100 stack-based overflow
A local attacker can exploit a stack-based buffer overflow in the Wincor PORT IO Driver to execute arbitrary code or escalate privileges.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-5555?
CVE-2025-5555 is a high-severity memory corruption vulnerability in Nixdorf Wincor PORT IO Driver, published on 18 Oct 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A vulnerability has been found in Nixdorf Wincor PORT IO Driver up to 1.0.0.1. This affects the function sub_11100 in the library wnport.sys of the component IOCTL Handler. Such manipulation leads to stack-based buffer overflow. Local access is required to approach this attack. The exploit has been disclosed to the public and may be used. Upgrading to version 3.0.0.1 is able to mitigate this issue. Upgrading the affected component is recommended. The vendor was contacted beforehand and was able to provide a patch very early.
Which versions are affected by CVE-2025-5555?
How do I fix CVE-2025-5555?
No fix has been published for CVE-2025-5555 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2025-5555 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-5555 exists.
Sources
Also known as GHSA-9gv5-442j-6rr2.