Is CVE-2026-20031 in the CISA KEV catalog?

No. CVE-2026-20031 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-20031?

CVE-2026-20031 has a CVSS v3 base score of 5.3 (MEDIUM).

What is the EPSS score for CVE-2026-20031?

CVE-2026-20031 has an EPSS score of 0.41% (33th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-20031?

Upgrade clamav on debian unstable to 1.4.4+dfsg-1 or later.

CVE & CISA-KEV Catalog

CVE-2026-20031

MEDIUM

5.3

CVSS v3

NVD

Description

A vulnerability in the HTML Cascading Style Sheets (CSS) module of ClamAV could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper error handling when splitting UTF-8 strings. An attacker could exploit this vulnerability by submitting a crafted HTML file to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to terminate the scanning process.

CWE-248

How to fix

Remediation Available

clamavDebian

Fixed in:1.4.4+dfsg-1CVE-2026-20031

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityLow

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Exploit Intelligence

0.41%probability of exploitation in 30 days

33rdpercentile

Low risk: more likely to be exploited than 33% of all known CVEs.

References

Other references1

sec.cloudapps.cisco.com

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-05.