CVE-2026-20243: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') in Cisco Cisco Secure Endpoint
A vulnerability in the ALZ 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 ALZ 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 ALZ 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.
AI Analysis
Technical Summary
This vulnerability arises from improper boundary checks in the ALZ file format parser used by ClamAV within Cisco Secure Endpoint. Specifically, an out-of-bounds buffer write can occur during scanning of crafted ALZ files, potentially causing the ClamAV scanning process to crash and resulting in a denial-of-service condition. The vulnerability is exploitable remotely without authentication by submitting malicious ALZ files to the scanning engine. The CVSS v3.1 base score is 7.5, reflecting high severity due to the ease of exploitation and impact on availability. Affected versions are numerous and explicitly enumerated, but no vendor advisory or patch information is currently available.
Potential Impact
Successful exploitation results in a denial-of-service condition by causing the ClamAV scanning process within Cisco Secure Endpoint to terminate unexpectedly due to memory corruption. There is no confirmed impact on confidentiality or integrity. The vulnerability can be triggered remotely by unauthenticated attackers submitting crafted ALZ files for scanning.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, consider restricting or monitoring the submission of ALZ files for scanning if possible to reduce exposure. No vendor advisory or official remediation instructions have been provided at this time.
CVE-2026-20243: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') in Cisco Cisco Secure Endpoint
Description
A vulnerability in the ALZ 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 ALZ 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 ALZ 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.
CVSS v3.1
Score 7.5high
Affected software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability arises from improper boundary checks in the ALZ file format parser used by ClamAV within Cisco Secure Endpoint. Specifically, an out-of-bounds buffer write can occur during scanning of crafted ALZ files, potentially causing the ClamAV scanning process to crash and resulting in a denial-of-service condition. The vulnerability is exploitable remotely without authentication by submitting malicious ALZ files to the scanning engine. The CVSS v3.1 base score is 7.5, reflecting high severity due to the ease of exploitation and impact on availability. Affected versions are numerous and explicitly enumerated, but no vendor advisory or patch information is currently available.
Potential Impact
Successful exploitation results in a denial-of-service condition by causing the ClamAV scanning process within Cisco Secure Endpoint to terminate unexpectedly due to memory corruption. There is no confirmed impact on confidentiality or integrity. The vulnerability can be triggered remotely by unauthenticated attackers submitting crafted ALZ files for scanning.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, consider restricting or monitoring the submission of ALZ files for scanning if possible to reduce exposure. No vendor advisory or official remediation instructions have been provided at this time.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- cisco
- Date Reserved
- 2025-10-08T11:59:15.400Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a45492827e9c79719d62057
Added to database: 07/01/2026, 17:06:48 UTC
Last enriched: 07/01/2026, 17:24:23 UTC
Last updated: 07/01/2026, 21:50:14 UTC
Views: 6
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