CVE-2026-123585

Hickory DNS 0.25.0 before 0.26.2 Query Amplification via Irrelevant CNAME Records

CVSS 4.0 6.9 MEDIUMCVSS 3.1 5.3 MEDIUMEUVD CVSS 4.0 6.9 CVSS 4.0 · [email protected] · Secondary 6.9 MEDIUMCVSS 3.1 · [email protected] · Secondary 5.3 MEDIUMCVSS_V4 Publisher rating MODERATEFixed by hickory-resolver 0.26.2KEV status unknown

Original advisory

cve-program · CVE-2026-123585

Published

The hickory-resolver component of Hickory DNS 0.25.0 before 0.26.2 follows irrelevant CNAME records when resolving recursive queries, sending queries that are unnecessary to answer the original request. Attackers controlling DNS responses can include CNAME records in the authority or additional sections, or outside the original query name's CNAME chain, causing excess resolver queries and increased query amplification.

Read the publisher's advisory

euvd · EUVD-2026-119344

Published

Read the publisher's advisory

nvd · CVE-2026-123585

Published

Read the publisher's advisory

osv · GHSA-6f2x-v7q7-m7m5

Published

When the Hickory DNS resolver follows CNAME records, it sends queries that are not necessary to answer the original recursive query. If there are any CNAME records in the authority section or additional section of the response, queries will be sent for those names. If there are any CNAME records that are not part of a CNAME chain starting from the original recursive query name, queries will be sent for those names. This increases query amplification beyond what is necessary to answer the recursive query.

Read the publisher's advisory

Affected versions, risk and source history

cve-program · CVE-2026-123585

Published

hickory-dns

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "vendor": "hickory-dns",
                    "product": "hickory-dns",
                    "defaultStatus": "unaffected",
                    "packageURL": "pkg:cargo/hickory-resolver",
                    "versions": [
                        {
                            "version": "0.25.0",
                            "status": "affected",
                            "versionType": "semver",
                            "lessThan": "0.26.2"
                        },
                        {
                            "version": "0.26.2",
                            "status": "unaffected",
                            "versionType": "semver"
                        }
                    ]
                }

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

euvd · EUVD-2026-119344

Published

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 10, 2026, 5:57:43 PM

No normalized affected-package data is projected for this source revision. The original publisher record may contain additional product and version evidence; this does not establish that a package is unaffected.

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

nvd · CVE-2026-123585

Published

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: 2026-11-08T02:16:52.327

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

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

osv · GHSA-6f2x-v7q7-m7m5

Published

hickory-resolver

crates.io

SEMVER · introduced 0.25.0 → fixed 0.26.2

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