What is CVE-2021-27506?

CVE-2021-27506 is a medium-severity vulnerability in Clamav. CVSS score: 5.5/10. Published 2021-03-19.

How severe is CVE-2021-27506?

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

Vulnerability in Clamav

CVE-2021-27506

The ClamAV Engine (version 0.103.1 and below) component embedded in Storsmshield Network Security (SNS) is subject to DoS in case of parsing of malformed png files. This affect Netasq versions 9.1.0 to 9.1.11 and SNS versions 1.0.0 to 4.2.0. This issue is fixed in SNS 3.7.19, 3.11.7 and 4.2.1.

Published 2021-03-19 · 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: 0.013 (69.5th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 70th percentile — 69.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.013 · newest: 0.013 · change: 0.000

Affected products

References

advisories.stormshield.eu/2021-003/ (Broken Link, Vendor Advisory)
blog.clamav.net/2021/02/clamav-01031-patch-release.html (Vendor Advisory)

Frequently asked questions

What is CVE-2021-27506?: CVE-2021-27506 is a medium-severity vulnerability in Clamav. CVSS score: 5.5/10. Published 2021-03-19.
How severe is CVE-2021-27506?: Medium severity. CVSS v3 base score is 5.5 out of 10.