Wincor Nixdorf wnBios64.sys 1.2.0.0 IOCTL stack-based overflow

Summaryinfo

A vulnerability identified as critical has been detected in Wincor Nixdorf wnBios64.sys 1.2.0.0. This vulnerability affects unknown code of the component IOCTL Handler. The manipulation leads to stack-based overflow. This vulnerability is listed as CVE-2025-70616. There is no available exploit.

Detailsinfo

A vulnerability was found in Wincor Nixdorf wnBios64.sys 1.2.0.0. It has been rated as critical. This issue affects some unknown functionality of the component IOCTL Handler. The manipulation with an unknown input leads to a stack-based overflow vulnerability. Using CWE to declare the problem leads to CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). Impacted is confidentiality, integrity, and availability. The summary by CVE is:

A stack buffer overflow vulnerability exists in the Wincor Nixdorf wnBios64.sys kernel driver (version 1.2.0.0) in the IOCTL handler for code 0x80102058. The vulnerability is caused by missing bounds checking on the user-controlled Options parameter before copying data into a 40-byte stack buffer (Src[40]) using memmove. An attacker with local access can exploit this vulnerability by sending a crafted IOCTL request with Options > 40, causing a stack buffer overflow that may lead to kernel code execution, local privilege escalation, or denial of service (system crash). Additionally, the same IOCTL handler can leak kernel addresses and other sensitive stack data when reading beyond the buffer boundaries.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2025-70616 since 01/09/2026. The exploitation is known to be easy. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 03/11/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2025-208323). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Vendor

• Wincor Nixdorf

Name

• wnBios64.sys

Version

• 1.2.0.0

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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