CVE intelligence

CVE-2026-20338

Vulnerability intelligence

Published Aug 7, 2026Sources checked Oct 27, 2026

7.5HIGHCVSS out of 10

What this means

Review the available evidence

CVE-2026-20338 and is rated High severity with a CVSS score of 7.5. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Aug 23, 2026

CBL-Mariner Releases

Vendor-listed releases

1.5.4-1

Cisco Security Advisories guidance

Vendor revision: Aug 13, 2026

Cisco has released software updates that address these vulnerabilities in affected Cisco platforms.

CISA KEVNot listedBased on the latest collected catalog

EPSS0.6%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-20338?

A vulnerability in the zip archive parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition on an affected device.

This vulnerability is due to improper memory handling when processing content in zip files during scanning. An attacker could exploit this vulnerability by submitting a crafted zip file for scanning.

A successful exploit could allow the attacker to cause the ClamAV scanning process to terminate as a result of a memory double-free, resulting in a DoS condition on the affected software.

Source: NVD