CVE-2026-20243: ClamAV ALZ Archive Processing Denial of Service Vulnerability
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.
Other sources
ClamAV ALZ Archive Processing Denial of Service Vulnerability
— Microsoft
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/clamavto a version that resolves this vulnerability.Fixed in 1.4.5+dfsg-2 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 1.5.3-1
Event History
Frequently Asked Questions
What is the severity of CVE-2026-20243?
CVE-2026-20243 has a high severity rating of 7.5.
How do I fix CVE-2026-20243?
To mitigate CVE-2026-20243, update ClamAV to the latest version provided by the vendor.
What impact does CVE-2026-20243 have on ClamAV?
CVE-2026-20243 allows an unauthenticated remote attacker to cause a denial of service condition on affected devices.
What causes CVE-2026-20243?
CVE-2026-20243 is caused by improper boundary checks in the ALZ file format parser within ClamAV.
Can CVE-2026-20243 be exploited remotely?
Yes, CVE-2026-20243 can be exploited by an unauthenticated remote attacker.