CVE-2026-20339: A vulnerability in the PESpin file format parser of ClamAV could allow an unauthenticated, remote attacker to

This month

HIGH 7.5REMOTE

CVE-2026-20339 is a high-severity flaw (CVSS 7.5) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 61%)
CISA exploited list	No
Weakness	CWE-190
Published	2026-08-07
Last modified	2026-10-23

Publisher (CNA): Cisco Systems, Inc.

Timeline

2026-08-07 17:17 UTCPublished CVE record published
2026-10-23 20:10 UTCUpdated Record last modified

Exact fixes by distribution

Fedora 46 · clementine · FIXED · 1.4.2-1.fc46 · FEDORA-2026-3e748ef4d3 · source

sudo dnf upgrade --advisory=FEDORA-2026-3e748ef4d3

Ubuntu 22.04 · clamav · FIXED · 1.5.4+dfsg-0ubuntu0.22.04.1

sudo apt update && sudo apt install --only-upgrade clamav dpkg --compare-versions "$(dpkg-query -W -f='${Version}' clamav)" ge "1.5.4+dfsg-0ubuntu0.22.04.1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.04 · clamav · FIXED · 1.5.4+dfsg-0ubuntu0.24.04.1

sudo apt update && sudo apt install --only-upgrade clamav dpkg --compare-versions "$(dpkg-query -W -f='${Version}' clamav)" ge "1.5.4+dfsg-0ubuntu0.24.04.1" && echo PATCHED || echo STILL-VULNERABLE

Debian 12 · clamav · FIXED · 1.4.6+dfsg-0+deb12u1

sudo apt update && sudo apt install --only-upgrade clamav dpkg --compare-versions "$(dpkg-query -W -f='${Version}' clamav)" ge "1.4.6+dfsg-0+deb12u1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · clamav · NO FIX YET

Alpine 3.24 · clamav · FIXED · clamav-1.4.6-r0

apk add --upgrade clamav apk info -v clamav

Amazon Linux 2023 · see advisory · FIXED · ALAS2023-2026-2116 · source

sudo dnf update --advisory=ALAS2023-2026-2116

Amazon Linux 2 · see advisory · FIXED · ALAS2-2026-3894 · source

sudo yum update --advisory=ALAS2-2026-3894

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Write-up: sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-clamav-Wuuv

Advisories and coverage

Official advisories

Amazon Linux 2 ALAS: ALAS2-2026-3894 (important): clamav1.4 2026-08-31

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

References

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