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HighVulnerabilityupdated 25 Oct 2026, 15:20 UTC

ClamAV antivirus has flaws that can crash it or leak information

ClamAV is a free antivirus scanner. Attackers on the network can exploit these flaws to crash the scanner or read data they should not see.

Official source
SeverityHighVulnerability
Being exploited?UnclearNo reports either way yet
Fix available?UnclearNo fixed version published in the sources yet
How sure is this?Official sourceBacked by an official source

What happened

Multiple vulnerabilities in ClamAV allow a remote, anonymous attacker to cause a denial of service and disclose information. Several separate advisories have been issued.

Why it is dangerous: A crashed scanner stops checking files, and information disclosure can expose sensitive data handled by the scanner. Servers and mail gateways running ClamAV are most at risk.

Are you affected?

You are affected if you run a ClamAV version listed as vulnerable in the BSI advisories on a system reachable by remote users, such as a mail gateway or file-upload server.

ClamAV (exact affected versions not stated in the provided material)

What to do

  1. Check the official ClamAV release notes and BSI advisory for the fixed version
  2. Update ClamAV to the fixed version on all servers and gateways
  3. Restrict network access to the ClamAV service where possible

Timeline

  1. 23 Oct 2026, 10:25 UTC
    Publicly disclosed
  2. 23 Oct 2026, 10:25 UTC
    Reported by CERT-Bund (BSI) · CERT-Bund (BSI)
  3. 23 Oct 2026, 10:25 UTC
    Reported by CERT-Bund (BSI) · CERT-Bund (BSI)
  4. 23 Oct 2026, 10:25 UTC
    Reported by CERT-Bund (BSI) · CERT-Bund (BSI)
  5. 25 Oct 2026, 15:20 UTC
    Picked up by Zero Radar

Sources 3 reports, oldest first

Official vendor, government CERT or advisory database

Technical details

ID
ZR-a4875a5b · ZR-697ed9cf · ZR-0c0d0746
Disclosed
23 Oct 2026, 10:25 UTC
On Zero Radar
25 Oct 2026, 15:20 UTC (2 days after disclosure)
Last change
25 Oct 2026, 15:20 UTC

The plain-language parts and the attack diagram were written by an AI model (anthropic/claude-haiku-5.5) from the sources above. Facts like versions, exploitation and dates come from the sources themselves. How Zero Radar works

ClamAV antivirus has flaws that can crash it or leak information · Zero Radar