CVE-2026-20338 ClamAV ZIP File Format Processing Memory Corruption Vulnerability
An unauthenticated remote attacker can cause a denial of service by submitting a crafted zip file that triggers a double-free error in ClamAV.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-20338?
CVE-2026-20338 is a high-severity memory corruption vulnerability in Cisco Secure Endpoint, published on 7 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-415
Which versions are affected by CVE-2026-20338?
How do I fix CVE-2026-20338?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-20338 being exploited?
There is no known exploitation of CVE-2026-20338 in the wild and no public exploit code.
Sources
Also known as AZL-95459, GHSA-xw98-8fcm-j8x7, UBUNTU-CVE-2026-20338.