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 update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-27506 is rated Low Risk (39.6/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.27%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-27506

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-25 0.19% 0.27% +0.08%
2 2025-12-28 0.14% 0.19% +0.05%
3 2025-12-27 — 0.14% —

Full EPSS history (17 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-27506

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2021-27506

Affected software / configurations for CVE-2021-27506

Vendor Product Version Raw CPE
netasq_project netasq >= 9.1.0, <= 9.1.11 cpe:2.3:a:netasq_project:netasq:*:*:*:*:*:*:*:*
stormshield stormshield_network_security >= 1.0, <= 4.2.0 cpe:2.3:a:stormshield:stormshield_network_security:*:*:*:*:*:*:*:*
clamav clamav <= 0.103.1 cpe:2.3:a:clamav:clamav:*:*:*:*:*:*:*:*

References for CVE-2021-27506

cvelogic Threat Intelligence