RUSTSEC-2026-0516Published

Hickory DNS 0.25.0-alpha.3 through 0.25.2 Query Amplification via Cyclic Referrals

Exploitation and risk

CISA KEV lists vulnerabilities known to be exploited. FIRST EPSS estimates the likelihood of exploitation in the next 30 days. An unavailable score does not mean zero risk.

Which CVEs have scores here?

This view includes predictions for CVE identifiers explicitly listed in public NuGet advisories. Microsoft release pages have their own prediction coverage. Check source status for the scope and latest checks.

No exploitation or prediction data is available here for these CVEs. This does not mean they are safe or unlikely to be exploited.

cve-program · CVE-2026-123586

Published

Hickory DNS 0.25.0-alpha.3 through 0.25.2 contains a query amplification vulnerability in its recursive resolver, which mishandles cyclic sibling name server referrals that lack glue records. Attackers controlling two zones whose name servers reference each other without glue records can make the recursor loop, sending many upstream queries, amplified further by zero-TTL NS records.

Source published: 8 Nov 2026 01:38:18 UTC
Source modified: 9 Nov 2026 13:54:36 UTC
Saved here: 9 Nov 2026 15:02:10 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 4.0 · 8.7 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

CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

euvd · EUVD-2026-119345

Published

Additional publisher context

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: Nov 8, 2026, 1:38:18 AM

dateUpdated: Nov 9, 2026, 1:54:36 PM

Source published: Nov 8, 2026, 1:38:18 AM (timezone not stated)
Source modified: Nov 9, 2026, 1:54:36 PM (timezone not stated)
Saved here: 12 Nov 2026 15:19:05 UTC
Source terms: ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

Source: euvd · ENISA EUVD · source terms and attribution apply. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

EUVD CVSS 4.0 · 8.7 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

nvd · CVE-2026-123586

Published

Additional publisher context

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Deferred

Weakness classifications: CWE-400

Original publisher date fields

published: 2026-11-08T02:16:52.477

lastModified: 2026-11-10T22:15:59.797

Source published: 8 Nov 2026 02:16:52 UTC
Source modified: 10 Nov 2026 22:15:59 UTC
Saved here: 12 Nov 2026 15:18:38 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

Source: nvd · NIST NVD usage terms; underlying source attribution retained. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 4.0 · [email protected] · Secondary · 8.7 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS 3.1 · [email protected] · Secondary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

osv · RUSTSEC-2026-0516

Published

Two zones can each delegate to name servers named only inside the other zone, with no glue records (the cyclic sibling case in RFC 9471 section 2.3). Such delegations can never be resolved, but the recursor did not stop when it came back to a zone it was already resolving. It kept sending queries until the per-request limits ran out, and zero TTLs on the referral NS records made this worse. Someone who controls two such zones can make a recursor send many upstream queries for each client query. This affects the recursive resolver, which is in hickory-resolver behind the opt-in `recursor` feature from 0.26.0-beta.1. Earlier releases shipped it as the separate hickory-recursor crate. From 0.26.2 each client request tracks the zones on its resolution stack and refuses to enter a zone that is already on it.

Source published: 3 Sep 2026 12:00:00 UTC
Source modified: 12 Nov 2026 14:40:46 UTC
Saved here: 12 Nov 2026 15:18:33 UTC
Source terms: OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

Source: osv · OSV · upstream source license applies. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

osv · RUSTSEC-2026-0522

Published

Two zones can each delegate to name servers named only inside the other zone, with no glue records (RFC 9471 section 2.3). The recursor did not stop when it came back to a zone it was already resolving, so someone who controls two such zones can make it send many upstream queries for each client query. The recursor code moved into hickory-resolver (opt-in `recursor` feature) in 0.26.0-beta.1, and the fix is in hickory-resolver 0.26.2. No hickory-recursor release contains a fix, so users should move to hickory-resolver 0.26.2 or later with the `recursor` feature.

Source published: 3 Sep 2026 12:00:00 UTC
Source modified: 12 Nov 2026 14:40:46 UTC
Saved here: 12 Nov 2026 15:18:33 UTC
Source terms: OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

Source: osv · OSV · upstream source license applies. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.