Knot Resolver before 5.6.0 enables attackers to consume its resources, launching amplification attacks and potentially causing a denial of service. Specifically, a single client query may lead to a hundred TCP connection attempts if a DNS server closes connections without providing a response.

DNSSEC validation is not performed correctly. An attacker can cause this package to report successful validation for invalid, attacker-controlled records. Root DNSSEC public keys are not validated, permitting an attacker to present a self-signed root key and delegation chain.

DNSSEC validation is not performed correctly. An attacker can cause this package to report successful validation for invalid, attacker-controlled records. The owner name of RRSIG RRs is not validated, permitting an attacker to present the RRSIG for an attacker-controlled domain in a response for any other domain.

Cache Poisoning issue exists in DNS Response Rate Limiting.

Improper input validation bugs in DNSSEC validators components in Knot Resolver (prior version 1.5.2) allow attacker in man-in-the-middle position to deny existence of some data in DNS via packet replay.