CVE-2026-20216: ClamAV InstallShield File Format Processing Resource Exhaustion Vulnerability

highCVSS 7.5CVE-2026-20216

CSIRTS triage

vendor: ClamAV product: ClamAV Denial of service

What: A resource exhaustion vulnerability in InstallShield file format processing can occur.
Who is affected: Deployments of ClamAV are affected.
Urgency: Remediation is urgent due to the high severity and potential for denial of service.
Action: Update to the latest version of ClamAV.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: high — CVSS 7.5
Published: 2026-07-02
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20216

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-202160.39% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 31% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-20216	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

medium[UPDATE] [medium] ClamAV: Multiple vulnerabilitiescert-bund
unknownUSN-8517-1: ClamAV vulnerabilitiesubuntu
highClamAV Vulnerabilities Affecting Cisco Products: July 2026cisco-psirt
unknownMultiple vulnerabilities in ClamAV (July 2, 2026)cert-fr-avis
unknownMultiple vulnerabilities in Cisco products (July 2, 2026)cert-fr-avis
highCVE-2026-20216: A vulnerability in the InstallShield file format parser of ClamAV could allow an unauthenticat…nvd
highCisco Advance Notification for Publication of July 1, 2026, Security Advisoriescisco-psirt

Recent advisories for ClamAV InstallShield File

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

highCVE-2026-20216: A vulnerability in the InstallShield file format parser of ClamAV could allow an unauthenticat…nvd · 2026-07-01