GHSA-6f2x-v7q7-m7m5: Hickory resolver Hickory-resolver Follows Irrelevant CNAME Records Vulnerability

MODERATE
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CWE-400
Published
Advisory Summary

GHSA-6f2x-v7q7-m7m5 is a MODERATE hickory-resolver follows irrelevant cname records vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Hickory resolver libraries in the crates.io ecosystem. The issue involves hickory-resolver follows irrelevant cname records. Remediation is available by upgrading affected packages to version 0.26.2.

GHSA-6f2x-v7q7-m7m5 at a Glance

CVE Identifier N/A
GHSA Identifier GHSA-6f2x-v7q7-m7m5
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-400: Uncontrolled Resource Consumption
Affected Product Hickory resolver
Package Ecosystem crates.io
Published Date
Last Updated

How to Fix GHSA-6f2x-v7q7-m7m5

To remediate this vulnerability, upgrade all affected Hickory resolver dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

hickory-resolver fixed: 0.26.2 
Upgrade hickory-resolver to 0.26.2
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for hickory-resolver

How to Check if You Are Affected

To determine whether your application is affected by GHSA-6f2x-v7q7-m7m5, inspect your project dependencies for Hickory resolver:

inspect dependencies for hickory-resolver

Analyze the terminal output to locate any version of Hickory resolver in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.26.2), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-400: Uncontrolled Resource Consumption, where the product does not properly control the allocation and maintenance of a limited resource. In Hickory resolver, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

GHSA-6f2x-v7q7-m7m5 Affected Hickory resolver Versions

1 component(s)
Fixed Versions:
0.26.2
Product / Package Ecosystem Affected Versions Fixed Version
hickory-resolver
 crates.io
≥ 0.25.0
< 0.26.2
0.26.2

References

GitHub Advisory / Wiki ADVISORY
https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-6f2x-v7q7-m7m5
Hickory resolver Source Repository REPOSITORY
https://github.com/hickory-dns/hickory-dns/pull/3871
Security Fix Commit FIX COMMIT
https://github.com/hickory-dns/hickory-dns/commit/4689fc8d3ddd3e3f99ec1b7be4e2e9e78afd2e6b
Security Fix Commit FIX COMMIT
https://github.com/hickory-dns/hickory-dns/commit/ccd6952378f250c714fc2af0cb1053e1c179f832
Hickory resolver Source Repository REPOSITORY
https://github.com/hickory-dns/hickory-dns
Hickory resolver Release RELEASE
https://github.com/hickory-dns/hickory-dns/releases/tag/v0.26.2

Frequently Asked Questions

What is GHSA-6f2x-v7q7-m7m5?
GHSA-6f2x-v7q7-m7m5 is a security vulnerability in Hickory resolver involving hickory-resolver follows irrelevant CNAME records under CWE-400: Uncontrolled Resource Consumption.
Which Hickory resolver versions are affected?
Affected versions include releases prior to 0.26.2 across affected packages: hickory-resolver.
What version fixes GHSA-6f2x-v7q7-m7m5?
Upgrading to 0.26.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is hickory-resolver affected?
Yes, hickory-resolver is affected in releases prior to 0.26.2. Upgrade your dependency to 0.26.2 or later.
What CWE is associated with GHSA-6f2x-v7q7-m7m5?
GHSA-6f2x-v7q7-m7m5 is classified under CWE-400: Uncontrolled Resource Consumption (The product does not properly control the allocation and maintenance of a limited resource.).
How can I check crates.io dependencies for GHSA-6f2x-v7q7-m7m5?
Run the dependency tree command: 'inspect dependencies for hickory-resolver'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-6f2x-v7q7-m7m5",
  "modified" : "2026-10-05T22:55:18Z",
  "published" : "2026-10-05T22:55:18Z",
  "aliases" : [ ],
  "summary" : "hickory-resolver follows irrelevant CNAME records",
  "details" : "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.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "hickory-resolver"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.25.0"
      }, {
        "fixed" : "0.26.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-6f2x-v7q7-m7m5"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/hickory-dns/hickory-dns/pull/3871"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/hickory-dns/hickory-dns/commit/4689fc8d3ddd3e3f99ec1b7be4e2e9e78afd2e6b"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/hickory-dns/hickory-dns/commit/ccd6952378f250c714fc2af0cb1053e1c179f832"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/hickory-dns/hickory-dns"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/hickory-dns/hickory-dns/releases/tag/v0.26.2"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-10-05T22:55:18Z",
    "nvd_published_at" : null
  }
}