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VulnerabilityPublished Updated

CVE-2025-70616: wnBios64.sys · Stack-based Buffer Overflow

Affects wnBios64.sysSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High.

Data as of 26 Oct 2026, 12:55 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 15% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 5 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
GitHub250wuyifan/wnBios64.syspkg:github/250wuyifan/wnBios64.sysOther threatsAffected
  • =1.2.0.0
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Given the absence of official patches, organizations should implement several targeted mitigations: 1) Restrict local access to systems running the vulnerable wnBios64.sys driver by enforcing strict physical and logical access controls, including limiting administrative privileges and using strong authentication mechanisms. 2) Employ application whitelisting and endpoint detection and response (EDR) solutions to monitor and block suspicious IOCTL calls or attempts to interact with the vulnerable driver. 3) Use kernel-mode exploit mitigation technologies such as Kernel Control Flow Guard (KCFG) or Kernel Patch Protection where supported to reduce the risk of successful kernel code execution. 4) Monitor system logs and audit IOCTL requests for anomalous activity related to the 0x80102058 handler. 5) Segment networks to isolate critical Wincor Nixdorf systems, minimizing the risk of lateral movement from compromised hosts. 6) Engage with Wincor Nixdorf or authorized vendors to obtain updates or patches as soon as they become available. 7) Conduct regular security assessments and penetration tests focusing on local privilege escalation vectors. These steps go beyond generic advice by focusing on controlling local access, monitoring specific driver interactions, and leveraging kernel exploit mitigations.

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.

References

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