CVE-2026-20217 in ClamAV
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, resulting from 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 out-of-bounds buffer write. 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.
Quick answer
Cisco Talos ClamAV should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- ClamAV 1.5.2, 1.4.4, and earlier versions back to 2005
Fixed versions
- ClamAV 1.5.3 or 1.4.5 or later
How to fix it
CVE-2026-20217 affects ClamAV. In simple terms, an attacker may be able to make the service slow or stop if the affected part is exposed or receives unsafe input. Update to ClamAV 1.5.3 or 1.4.5 or later. If you cannot update now, limit access until the fix is installed.
- Find every ClamAV install and check its version.
- Update to ClamAV 1.5.3 or 1.4.5 or later.
- If you cannot update today, block public access to the risky feature or service.
- Review logs for strange access, crashes, deleted files, or failed requests.
- Rotate secrets if you think the issue may have been used.
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Verify the fix
- Confirm the installed version is fixed or the mitigation is active.
- Test the affected feature with a normal user account.
- Confirm untrusted users cannot reach the risky path or service.
- Run a fresh Fixnx scan and keep the result with your change record.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-20217?
Cisco Talos ClamAV versions listed as affected should be reviewed: ClamAV 1.5.2, 1.4.4, and earlier versions back to 2005.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.