Input validation error in ClamAV - CVE-2026-20243
Published: July 1, 2026
Vulnerability identifier: #VU136663
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-20243
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: ClamAV
Affected software:
ClamAV
ClamAV
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to improper size handling in the ALZ parser when parsing a malformed ALZ archive. A remote attacker can provide a specially crafted archive to cause a denial of service.
The issue may panic or abort the scanner, and it may also skip expected scan-limit handling.
How to mitigate CVE-2026-20243
Install security update from vendor's website.