ClamAV CSS Module DoS via Crafted HTML (CVE-2026-20031)
CVE-2026-20031 Published on March 4, 2026

ClamAV CSS Image Parsing Error Handling Denial of Service Vulnerability
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.

NVD

Vulnerability Analysis

CVE-2026-20031 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a small impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
LOW

Weakness Type

Uncaught Exception

An exception is thrown from a function, but it is not caught. When an exception is not caught, it may cause the program to crash or expose sensitive information.


Products Associated with CVE-2026-20031

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Cisco Secure Endpoint
 

Affected Versions

Cisco Secure Endpoint:

Exploit Probability

EPSS
0.09%
Percentile
26.13%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.