CVE-2026-20243

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 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-clamav-88cFYyxR	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:cisco:secure_endpoint::::::macos::*
	cpe:2.3:a:cisco:secure_endpoint::::::linux::*
	cpe:2.3:a:cisco:secure_endpoint::::::windows::*

Configuration 2 (hide)

OR	cpe:2.3:a:clamav:clamav::::::::
	cpe:2.3:a:clamav:clamav::::::::

History

09 Jul 2026, 18:03

Type	Values Removed	Values Added
First Time		Cisco secure Endpoint Cisco Clamav clamav Clamav
CPE		cpe:2.3:a:cisco:secure_endpoint::::::windows::* cpe:2.3:a:cisco:secure_endpoint::::::linux::* cpe:2.3:a:cisco:secure_endpoint::::::macos::* cpe:2.3:a:clamav:clamav::::::::
References	~~() https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-clamav-88cFYyxR -~~	() https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-clamav-88cFYyxR - Vendor Advisory

01 Jul 2026, 17:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-07-01 17:16

Updated : 2026-07-09 18:03

NVD link : CVE-2026-20243

Mitre link : CVE-2026-20243

CVE.ORG link : CVE-2026-20243

JSON object : View

Products Affected

clamav

clamav

cisco

secure_endpoint

CWE

CWE-120

Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

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{"status": "affected", "version": "7.4.1.20425"}, {"status": "affected", "version": "7.4.1.20439"}, {"status": "affected", "version": "7.4.3"}, {"status": "affected", "version": "7.4.3.20679"}, {"status": "affected", "version": "7.4.5"}, {"status": "affected", "version": "7.5.1.20813"}, {"status": "affected", "version": "7.5.1.20833"}, {"status": "affected", "version": "7.5.3"}, {"status": "affected", "version": "7.5.5"}, {"status": "affected", "version": "8.0.1.21160"}, {"status": "affected", "version": "8.0.1.21164"}, {"status": "affected", "version": "7.5.7"}, {"status": "affected", "version": "7.5.9"}, {"status": "affected", "version": "7.5.11"}, {"status": "affected", "version": "8.1.7.21585"}, {"status": "affected", "version": "7.5.13.21586"}, {"status": "affected", "version": "7.5.13.21598"}, {"status": "affected", "version": "8.2.1.21612"}, {"status": "affected", "version": "8.2.1.21650"}, {"status": "affected", "version": "7.5.15.21611"}, {"status": "affected", "version": 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"description": [{"lang": "en", "value": "CWE-120"}]}], "descriptions": [{"lang": "en", "value": "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.\r\n\r\nThis 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."}], "lastModified": "2026-07-09T18:03:17.357", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:cisco:secure_endpoint:*:*:*:*:*:macos:*:*", "vulnerable": true, "matchCriteriaId": "E534D1FF-B590-40F3-9874-AC2BDA807087", "versionEndExcluding": "1.27.2"}, {"criteria": "cpe:2.3:a:cisco:secure_endpoint:*:*:*:*:*:linux:*:*", "vulnerable": true, "matchCriteriaId": "CB2B4CBA-534A-4111-8920-8580B12C4F46", "versionEndExcluding": "1.29.0"}, {"criteria": "cpe:2.3:a:cisco:secure_endpoint:*:*:*:*:*:windows:*:*", "vulnerable": true, "matchCriteriaId": "4EB7F99A-01AB-44EE-B682-5E2C9E7D2A4B", "versionEndExcluding": "8.6.2"}], "operator": "OR"}]}, {"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:clamav:clamav:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "162DF360-EF2A-499D-BDC9-F680594A6318", "versionEndExcluding": "1.4.5", "versionStartIncluding": "1.4.0"}, {"criteria": "cpe:2.3:a:clamav:clamav:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "5CC3C470-BBC6-449E-80F1-F9E762442D3C", "versionEndExcluding": "1.5.3", "versionStartIncluding": "1.5.0"}], "operator": "OR"}]}], "sourceIdentifier": "psirt@cisco.com"}