{"id":"CVE-2026-123604","title":"Hickory DNS 0.26.0-beta.1 before 0.26.2 Resource Exhaustion DoS via NameServerPool::try_send TC-Retry Loop","summary":"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 …","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cvssSource":"cna","cwe":["CWE-835"],"vendor":"hickory-dns","product":"hickory-dns","affected":["hickory-dns >= 0.26.0-beta.1 < 0.26.2"],"published":"2026-11-08","updated":"2026-11-08","sourceUpdated":"2026-11-08T01:38:31.351Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-123604","references":[{"url":"https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-6w6g-hm98-mhgm","label":"GitHub Security Advisory (GHSA-6w6g-hm98-mhgm)"},{"url":"https://www.vulncheck.com/advisories/hickory-dns-0.26.0-beta.1-before-0.26.2-resource-exhaustion-dos-via-nameserverpool-try-send-tc-retry-loop","label":"VulnCheck Advisory: Hickory DNS 0.26.0-beta.1 before 0.26.2 Resource Exhaustion DoS via NameServerPool::try_send TC-Retry Loop"}],"tags":["cve.org"],"ingestedAt":"2026-11-08T02:43:18.643Z","slug":"CVE-2026-123604","body":"## Overview\n\nHickory 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.\n\n## Affected\n\n- `hickory-dns >= 0.26.0-beta.1 < 0.26.2`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}