CVE-2025-70616: A stack buffer overflow vulnerability exists in the Wincor Nixdorf wnBios64.sys kernel driver (version 1.2.0.0

Routine

HIGH 7.8DOWNGRADE

CVE-2025-70616 is a high-severity flaw (CVSS 7.8) affecting wnbios64.sys. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 st

Why this priority

High severity
Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 84%)
CISA exploited list	No
Weakness	CWE-121
Published	2026-03-05
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: dieboldnixdorf

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-05 19:16 UTCPublished CVE record published
2026-06-17 10:03 UTCUpdated Record last modified

dieboldnixdorf wnbios64.sys DOWNGRADE

Affected: 1.2.0.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.2.0.0

1. Check installed version

apt-cache policy wnbios64.sys || rpm -q wnbios64.sys || wnbios64.sys --version

2. No fixed release: DOWNGRADE to a release before 1.2.0.0 (Debian / Ubuntu)

apt-cache madison wnbios64.sys sudo apt install wnbios64.sys=<VERSION_BEFORE_1.2.0.0> sudo apt-mark hold wnbios64.sys

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list wnbios64.sys sudo dnf downgrade wnbios64.sys-<VERSION_BEFORE_1.2.0.0> sudo dnf versionlock add wnbios64.sys

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-70616?

wnbios64.sys: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2025-70616 being exploited?

CVE-2025-70616 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-70616 affect?

CVE-2025-70616 affects wnbios64.sys. Severity is high (CVSS 7.8). 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

How urgent is CVE-2025-70616?

Priority 36/100. High severity; Public exploit reference

References

← Back to latest CVEs