CVE-2026-20337: A vulnerability in the zip archive parser of ClamAV could allow an unauthenticated, remote attacker to cause a

This month

HIGH 7.5REMOTE

CVE-2026-20337 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 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 boundary checks for content in zip files during scanning, which may result in an out-of-bounds write condition. An attacker could exploit this vulnerability by submitting a crafted zip file for scanning. A successful exploit could allow the attacker to cause th

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 57%)
CISA exploited list	No
Weakness	CWE-120
Published	2026-08-07
Last modified	2026-10-23

Publisher (CNA): Cisco Systems, Inc.

Last updated 2026-10-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

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

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

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.

Quick answers

How do I fix CVE-2026-20337?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Is CVE-2026-20337 being exploited?

CVE-2026-20337 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-20337 affect?

CVE-2026-20337 affects affected software. Severity is high (CVSS 7.5). 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 boundary checks for content in zip files during sca

How urgent is CVE-2026-20337?

Priority 42/100. High severity; Remotely exploitable, no login, no user action

References

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