CVE-2026-20031
published 2026-03-04CVE-2026-20031: 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)…
PriorityP431medium5.3CVSS 3.1
AVNACLPRNUINSUCNINAL
EPSS
0.44%
37.1th percentile
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.
Affected
162 ranges· showing 25
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
| cisco | cisco_secure_endpoint | — | — |
CVSS provenance
nvdv3.15.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
vendor_cisco5.3MEDIUM
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Cisco
ClamAV Cascading Style Sheets Image Parsing Error Handling Denial of Service Vulnerability
vendor_cisco·2026-03-04·CVSS 5.3
CVE-2026-20031 [MEDIUM] CWE-248 ClamAV Cascading Style Sheets Image Parsing Error Handling Denial of Service Vulnerability
ClamAV Cascading Style Sheets 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.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
This advisory is available at the following link:https://sec.cloudapps.cisco.com/security/center/co
Cisco
ClamAV Cascading Style Sheets Image Parsing Error Handling Denial of Service Vulnerability
vendor_cisco·CVSS 3.1
CVE-2026-20031 ClamAV Cascading Style Sheets Image Parsing Error Handling Denial of Service Vulnerability
CVE-2026-20031: ClamAV Cascading Style Sheets 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. Cisco has released software updates that address this vulnerability. There are no
CVSS: 3.1
CWE: CWE-248, CWE-248
Bug IDs: CSCwr70252, CSCwr70255, CSCwr70257, CSCwr70252, CSCwr70255
GHSA
GHSA-hvpm-hv6g-6m5c: A vulnerability in the HTML Cascading Style Sheets (CSS) module of ClamAV could allow an unauthenticated, remote attacker to cause a denial of service
ghsa_unreviewed·2026-03-04
CVE-2026-20031 [MEDIUM] CWE-248 GHSA-hvpm-hv6g-6m5c: A vulnerability in the HTML Cascading Style Sheets (CSS) module of ClamAV could allow an unauthenticated, remote attacker to cause a denial of service
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.
No detection rules found.
No public exploits indexed.
Wiz
CVE-2026-20031 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz·CVSS 8.6
CVE-2026-20031 [HIGH] CVE-2026-20031 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2026-20031 :
Clam AntiVirus vulnerability analysis and mitigation
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.
Source : NVD
## 5.3
Score
Published March 4, 2026
Severity MEDIUM
CNA Score 5.3
Affected Technologies
Clam AntiVirus
Has Public Exploit No
Has CISA KEV Exploit No
CISA KEV Release Date N/A
CISA KEV Due Date N/A
Exploitation Proba
Wiz
CVE-2020-37167 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz·CVSS 8.6
CVE-2020-37167 [HIGH] CVE-2020-37167 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2020-37167 :
Clam AntiVirus vulnerability analysis and mitigation
ClamAV versions prior to 0.103.0-rc contain a vulnerability in function name processing through the ClamBC bytecode interpreter that allows attackers to manipulate bytecode function names. Attackers can exploit the weak input validation in function name encoding to potentially execute malicious bytecode or cause unexpected behavior in the ClamAV engine.
Source : NVD
## 8.6
Score
Published February 12, 2026
Severity HIGH
CNA Score 8.6
Affected Technologies
Clam AntiVirus
Linux Ubuntu
Has Public Exploit Yes
Has CISA KEV Exploit No
CISA KEV Release Date N/A
CISA KEV Due Date N/A
Exploitation Probability Percentile (EPSS) 0.4
Exploitation Probability (EPSS) N/A
Affected packages and libraries
clamav
Bugzilla
CVE-2026-20031 clamav: improper error handling when splitting UTF-8 strings in the HTML Cascading Style Sheets (CSS) module [epel-all]
bugzilla·2026-03-04·CVSS 5.3
CVE-2026-20031 [MEDIUM] CVE-2026-20031 clamav: improper error handling when splitting UTF-8 strings in the HTML Cascading Style Sheets (CSS) module [epel-all]
CVE-2026-20031 clamav: improper error handling when splitting UTF-8 strings in the HTML Cascading Style Sheets (CSS) module [epel-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Discussion:
FEDORA-2026-ecf6fe868f (clamav-1.4.6-1.fc44) has been submitted as an update to Fedora 44.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-ecf6fe868f
---
FEDORA-EPEL-2026-3432a047a4 (clamav-1.4.6-1.el8) has been submitted as an update to Fedora EPEL 8.
https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2026-3432a047a4
---
FEDORA-2026-a9beec8485 (clamav-1.4.6-1.fc43) has been submitted as an update to Fedora 43.
ht
Bugzilla
CVE-2026-20031 ClamAV: improper error handling when splitting UTF-8 strings in the HTML Cascading Style Sheets (CSS) module
bugzilla·2026-03-04·CVSS 5.3
CVE-2026-20031 [MEDIUM] CVE-2026-20031 ClamAV: improper error handling when splitting UTF-8 strings in the HTML Cascading Style Sheets (CSS) module
CVE-2026-20031 ClamAV: improper error handling when splitting UTF-8 strings in the HTML Cascading Style Sheets (CSS) module
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.
Bugzilla
CVE-2026-20031 clamav: improper error handling when splitting UTF-8 strings in the HTML Cascading Style Sheets (CSS) module [fedora-all]
bugzilla·2026-03-04·CVSS 5.3
CVE-2026-20031 [MEDIUM] CVE-2026-20031 clamav: improper error handling when splitting UTF-8 strings in the HTML Cascading Style Sheets (CSS) module [fedora-all]
CVE-2026-20031 clamav: improper error handling when splitting UTF-8 strings in the HTML Cascading Style Sheets (CSS) module [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Discussion:
FEDORA-2026-ecf6fe868f (clamav-1.4.6-1.fc44) has been submitted as an update to Fedora 44.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-ecf6fe868f
---
FEDORA-EPEL-2026-b873ec0e0b has been pushed to the Fedora EPEL 10.3 testing repository.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2026-b873ec0e0b
See also https://fedoraproject.org/wiki/QA:Updates_Testing
2026-03-04
Published