CVE-2026-123604: high-severity vulnerability in hickory-dns
Hickory DNS 0.26.0-beta.1 before 0.26.2 Resource Exhaustion DoS via NameServerPool::try_send TC-Retry Loop
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
18Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.7
Hickory DNS hickory-resolver 0.26.0-beta.1 before 0.26.2 contains an unbounded retry loop in NameServerPool::try_send, which re-queues truncated (TC) responses without checking the answering transport or counting iterations. A malicious authoritative server returning TC=1 on every transport keeps the resolver spinning on a persistent TCP connection until the 5-second request deadline expires, causing resource exhaustion.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Affected products
hickory-dns · hickory-dnsRelated CVEs — hickory-dns
In the same product, most dangerous first.
CVE-2025-25188MEDIUMDNSSEC validation may accept broken authentication chainsEPSS 0.3%CVE-2026-123608HIGHHickory DNS hickory-proto 0.3.1 before 0.26.1 CPU Exhaustion via BinEncoder Name CompressionEPSS —CVE-2026-123607HIGHHickory DNS NSEC3 Closest-Encloser Proof Unbounded Loop Denial of ServiceEPSS —CVE-2026-123606HIGHHickory-DNS Recursor 0.25.0-alpha.3 through 0.25.2 Glueless-NS Referral AmplificationEPSS —CVE-2026-123605HIGHHickory DNS through 0.25.0-alpha.3 DNSSEC Validation Bypass via RRSIG Signer's NameEPSS —CVE-2026-123603MEDIUMHickory DNS Missing IPv4-Mapped IPv6 Canonicalization Access Control BypassEPSS —