CVE-2026-123604
Hickory DNS 0.26.0-beta.1 before 0.26.2 Resource Exhaustion DoS via NameServerPool::try_send TC-Retry Loop
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.
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| hickory-dns hickory-dns hickory-resolver
cargo |
≥ 0.26.0-beta.1; < 0.26.2 (affected, semver) 0.26.2 (unaffected, semver) Other versions: unaffected |
CNA: VulnCheck |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 8.7 high |
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 | CNA: VulnCheck |
| 3.1 / 7.5 high |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CNA: VulnCheck |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-6w6g-hm98-mhgmCNA: VulnCheck · vendor-advisory
- 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-loopCNA: VulnCheck · third-party-advisory
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