What is CVE-2021-42973?

CVE-2021-42973 is a high-severity vulnerability in Nomachine Server, classified under Integer Overflow or Wraparound. CVSS score: 8.8/10. Published 2021-12-07.

How severe is CVE-2021-42973?

High severity. CVSS v3 base score is 8.8 out of 10.

Integer overflow in Nomachine Server

CVE-2021-42973

NoMachine Server is affected by Integer Overflow. IOCTL Handler 0x22001B in the NoMachine Server above 4.0.346 and below 7.7.4 allow local attackers to execute arbitrary code in kernel mode or cause a denial of service (memory corruption and OS crash) via specially crafted I/O Request Packet.

Vulnerability class: Integer Overflow

Published 2021-12-07 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.005 (39.0th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 39th percentile — 39.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Nomachine Server

Weakness classification (CWE)

CWE-190 — Integer Overflow or Wraparound

References

www.sentinelone.com/labs/usb-over-ethernet-multiple-privilege-escalation-vulner… (Technical Description, Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2021-42973?: CVE-2021-42973 is a high-severity vulnerability in Nomachine Server, classified under Integer Overflow or Wraparound. CVSS score: 8.8/10. Published 2021-12-07.
How severe is CVE-2021-42973?: High severity. CVSS v3 base score is 8.8 out of 10.