CVE-2026-20339 ClamAV PESpin File Format Processing Integer Overflow Vulnerability
An unauthenticated remote attacker can cause a denial of service in ClamAV by submitting a crafted PESpin file that triggers an integer overflow.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-20339?
CVE-2026-20339 is a high-severity 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 PESpin file format parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition or possibly other expanded impacts as a result of memory corruption on an affected device. This vulnerability is due to improper boundary checks for content in PESpin files during scanning, which may result in an integer overflow. An attacker could exploit this vulnerability by submitting a crafted file that contains PESpin content to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to cause the ClamAV scanning process to terminate, resulting in a DoS condition on the affected software.
Weakness: CWE-190
Which versions are affected by CVE-2026-20339?
How do I fix CVE-2026-20339?
Upgrade to a fixed version.
Is CVE-2026-20339 being exploited?
There is no known exploitation of CVE-2026-20339 in the wild and no public exploit code.
Sources
Also known as AZL-95453, DEBIAN-CVE-2026-20339, GHSA-g59m-qx73-q3c6, UBUNTU-CVE-2026-20339.