CVE-2020-5591: Xack DNS

High severity, CVSS 7.5. EPSS: 1.6% chance of exploitation in the next 30 days.

XACK DNS 1.11.0 to 1.11.4, 1.10.0 to 1.10.8, 1.8.0 to 1.8.23, 1.7.0 to 1.7.18, and versions before 1.7.0 allow remote attackers to cause a denial of service condition resulting in degradation of the recursive resolver's performance or compromising the recursive resolver as a reflector in a reflection attack.

Affected products

• Xack Xack DNS: up to and including 1.7.18; from 1.8.0, up to and including 1.8.23; from 1.10.0, up to and including 1.10.8; from 1.11.0, up to and including 1.11.4

Published 2020-06-05. Last modified 2026-06-17.