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Medium severity · published Mar 4, 2026
CVE-2026-20031
ClamAV CSS Image Parsing Error Handling Denial of Service Vulnerability
5.3
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CS
Cisco Secure Endpoint · Cisco
7.0.5; 6.2.19; 7.3.3; 7.2.13; 6.1.5; 6.3.1; +34 more · source: vendor
Affected product
CS
Cisco Secure Endpoint
Cisco
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-20031
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-20031
sec.cloudapps.cisco.com
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-clamav-css-Fn4QSZ
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