What is CVE-2020-23884?

CVE-2020-23884 is a medium-severity vulnerability in Nomacs, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 5.5/10. Published 2021-11-10.

How severe is CVE-2020-23884?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Buffer overflow in Nomacs

CVE-2020-23884

A buffer overflow in Nomacs v3.15.0 allows attackers to cause a denial of service (DoS) via a crafted MNG file.

Vulnerability class: Buffer Overflow

Published 2021-11-10 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.010 (60.8th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 61st percentile — 60.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.010 · change: +0.000

Affected products

Nomacs — versions 3.15.0

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

References

nomacs.org/ (Vendor Advisory)
github.com/nomacs/nomacs/issues/516 (Exploit, Third Party Advisory)
github.com/Aurorainfinity/vulnerabilities/blob/master/nomacs/readme.md (Broken Link)

Frequently asked questions

What is CVE-2020-23884?: CVE-2020-23884 is a medium-severity vulnerability in Nomacs, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 5.5/10. Published 2021-11-10.
How severe is CVE-2020-23884?: Medium severity. CVSS v3 base score is 5.5 out of 10.