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PatchSiren cyber security CVE debrief

CVE-2026-20213 Cisco CVE debrief

A vulnerability in the PE 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 PE files during scanning, which may result in an out-of-bounds buffer write. The vulnerability affects ClamAV, which is used in Cisco Secure Endpoint. Users of Cisco Secure Endpoint and ClamAV should be aware of this vulnerability and take necessary actions to mitigate it. The debrief is based on the supplied source corpus and CVE record.

Vendor
Cisco
Product
Secure Endpoint
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-01
Original CVE updated
2026-07-09
Advisory published
2026-07-01
Advisory updated
2026-07-09

Who should care

Users of Cisco Secure Endpoint and ClamAV should be aware of this vulnerability and take necessary actions to mitigate it. This includes administrators of Cisco Secure Endpoint, security teams, and IT personnel responsible for maintaining and securing systems that use ClamAV. Additionally, operators and platform managers should review the vulnerability and assess their exposure to ensure that necessary precautions are taken.

Technical summary

The vulnerability is caused by improper boundary checks for content in PE 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 PE content to be scanned by ClamAV on an affected device. This vulnerability affects ClamAV, which is used in Cisco Secure Endpoint. Users of Cisco Secure Endpoint and ClamAV should be aware of this vulnerability and take necessary actions to mitigate it. The vulnerability can be mitigated by applying patches or updates provided by the vendor, implementing compensating controls, and conducting inventory checks to identify affected systems.

Defensive priority

High

Recommended defensive actions

  • Apply patches or updates provided by the vendor
  • Implement compensating controls, such as monitoring and exception tracking
  • Conduct inventory checks to identify affected systems
  • Restrict access to affected systems or services
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record was published on 2026-07-01T17:16:29.460Z and was last modified on 2026-07-09T17:56:55.537Z. The NVD entry is currently Analyzed. This information is based on the NVD entry and the CVE record. The vulnerability affects ClamAV, which is used in Cisco Secure Endpoint. Users should verify their systems for exposure and review vendor guidance. However, due to limited source detail, further verification and defensive measures are necessary.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-01T17:16:29.460Z and has not been modified since then. The NVD entry is currently Analyzed.