ClamAV Vulnerabilities Affecting Cisco Products: August 2026
Multiple vulnerabilities in ClamAV could allow a remote attacker to cause a denial of service (DoS) condition, interrupting scanning operations. For more information about these vulnerabilities, see the Details section of this advisory. For additional information on these vulnerabilities in ClamAV, see the ClamAV blog . Cisco has released software updates that address these vulnerabilities in affected Cisco platforms. There are no workarounds that address these vulnerabilities. Notes: The Security Impact Rating (SIR) for these vulnerabilities is High for Windows-based platforms only because those platforms run the ClamAV scanning process in a privileged security context. The platforms that are highly impacted include Cisco Secure Endpoint Connector for Windows. The SIR for these vulnerabilities is Medium on other platforms, including Linux and Mac platforms, because those platforms run the ClamAV scanning process in a lower-privileged security context. The affected platforms include Secure Endpoint Connector for Linux and Mac. Cisco Secure Endpoint Private Cloud itself is not impacted by these vulnerabilities. However, the Cisco Secure Endpoint Connector software that is distributed from the device is impacted. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-clamav-WuuvVd26 Security Impact Rating: High CVE: CVE-2026-20337,CVE-2026-20338,CVE-2026-20339,CVE-2026-20345,CVE-2026-20346,CVE-2026-20347,CVE-2026-20348
CSIRTS triage
- What
- Multiple vulnerabilities in ClamAV scanning engine allow remote attackers to cause denial of service by interrupting scanning operations.
- Who is affected
- Cisco Secure Endpoint Connector for Windows and other Cisco products using ClamAV; Windows platforms are highest impact due to privileged scanning context.
- Urgency
- High on Windows platforms due to elevated privilege context; no workarounds available.
- Action
- Apply Cisco software updates addressing these CVEs when released; prioritize Windows deployments.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
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-2026-203370.36% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 29% of all EPSS-scored CVEs.
- Low exploitation riskCVE-2026-203380.33% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 26% of all EPSS-scored CVEs.
- Low exploitation riskCVE-2026-203390.33% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 26% of all EPSS-scored CVEs.
- Low exploitation riskCVE-2026-203450.33% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 26% of all EPSS-scored CVEs.
- Low exploitation riskCVE-2026-203460.33% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 26% of all EPSS-scored CVEs.
- Low exploitation riskCVE-2026-203470.33% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 26% of all EPSS-scored CVEs.
- Low exploitation riskCVE-2026-203480.33% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 26% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-20337 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-20338 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-20339 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-20345 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-20346 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-20347 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-20348 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
- unknownexploitedCisco Products Multiple Vulnerabilitieshkcert
- high[NEW] [high] ClamAV: Multiple vulnerabilities allow Denial of Service and disclosure of informationcert-bund
- highCVE-2026-20346: ClamAV PDF File Format Processing Memory Corruption Vulnerabilitymsrc
- highCVE-2026-20348: ClamAV XAR File Format Processing Memory Corruption Vulnerabilitymsrc
- highCVE-2026-20339: ClamAV PESpin File Format Processing Integer Overflow Vulnerabilitymsrc
- highCVE-2026-20338: ClamAV ZIP File Format Processing Memory Corruption Vulnerabilitymsrc
- highCVE-2026-20347: ClamAV Mach-O File Format Processing Memory Corruption Vulnerabilitymsrc
- highCVE-2026-20345: ClamAV GPT File Format Processing Memory Corruption Vulnerabilitymsrc
- highCVE-2026-20337: ClamAV ZIP File Format Processing Memory Corruption Vulnerabilitymsrc
- unknownexploitedMultiple vulnerabilities in ClamAV (August 10, 2026)cert-fr-avis
- highCVE-2026-20348: A vulnerability in the XAR file format parser of ClamAV could allow an unauthenticated, remote…nvd
- highCVE-2026-20347: A vulnerability in the Mach-O file format parser of ClamAV could allow an unauthenticated, rem…nvd
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