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CVE-2026-123585

hickory-resolver follows irrelevant CNAME records

Products / packages hickory-dns · hickory-resolver

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Severity and exploitation

Not in CISA KEVSource: MODERATE

KEV coverage does not rule out exploitation.

KEV checked 15/11/2026, 01:40:32 UTC
OSV · CVSS:4.0 · 6.9
Assessment vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
VulnCheck · CVSS:4.0 · 6.9
Assessment vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
VulnCheck · CVSS:3.1 · 5.3
Assessment vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
The headline uses the highest imported catalog score. Assessments can differ by source and CVSS version.

Severity

medium6.9

CVSS measures technical severity, not the likelihood of an attack.

Known exploitation

Not listed in the checked CISA KEV catalog

Absence from CISA KEV does not rule out attacks.

Public exploit

Not established by this record

Missing evidence does not mean no public exploit exists.

Remediation

Package fixes recorded

Fix versions are recorded for 1 of 1 mapped packages. Check each release branch and any separate product guidance.

What this means

Hickory DNS resolver versions before 0.26.2 may send unnecessary queries due to following irrelevant CNAME records, potentially increasing query amplification. An attacker with the ability to control DNS responses may exploit this weakness. This is described as Uncontrolled Resource Consumption.

Summarized by @cf/meta/llama-3.3-70b-instruct-fp8-fast. Verify details against the original sources.

Attack conditions

No attack-condition excerpt has been identified here. Review the full source description and references for authentication, network access, and configuration requirements.

Review supporting sources →

Affected versions

Check the exact model, release, and any platform requirements against your installation.

hickory-dns · VulnCheck

hickory-dns

2 ranges
VulnCheck version evidence

Package identity

pkg:cargo/hickory-resolverExplore hickory-resolver →

Identity supplied by VulnCheck. Version matching requires compatible range evidence.

Compare with this publisher’s ranges. This does not inspect your installation.

affected

0.25.0 → before 0.26.2

semver versions

unaffected

0.26.2

semver versions

unknown

Other versions: unaffected

Packages

Compare each installed version with the publisher’s affected ranges. Where a fix is recorded, choose the appropriate release branch and test compatibility before upgrading.

hickory-resolver crates.io
Affected range Recorded fix
From 0.25.0 before 0.26.2Semantic versions0.26.2

Version evidence: OSV · GHSA-6f2x-v7q7-m7m5

View original version evidence (0 explicit versions)

What to do

Compare your installed product and version with the affected versions above. A matching product name alone does not confirm exposure.

Use the recorded fix for your release branch. Review the publisher’s instructions and test compatibility before upgrading.

cve.new guidance unless attributed to a publisher. This page does not inspect your installation.

Public exploit evidence

No public exploit reference is identified in the imported evidence. This is not a claim that no exploit exists.

Original source description

Read the full publisher description

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.

References

7 sources
hickory-dns/hickory-dns · security/advisories/GHSA-6f2x-v7q7-m7m5
Vendor advisoryVulnCheck
hickory-dns/hickory-dns · pull request #3871
Patch
hickory-dns/hickory-dns · commit 4689fc8
Patch
hickory-dns/hickory-dns · commit ccd6952
Patch
hickory-dns/hickory-dns · repository
Source reference
hickory-dns/hickory-dns · releases/tag/v0.26.2
Release notes
View 1 more references
www.vulncheck.com/advisories/hickory-dns-0.25.0-before-0.26.2-query-amplification-via-irrelevant-cname-records
Security advisoryVulnCheck

Inside the record

Evidence available

Package identity
Version evidence
Remediation guidance · not supplied
Weakness classification
Additional publishers

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2026-123585

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Underlying weaknesses

The source’s classification of what caused the vulnerability.

CWE-400 ↗

Uncontrolled Resource Consumption

VulnCheck

Related →
Contributing organizations · 2
VulnCheck

Assigning organization

2026-11-08
CISA-ADP

Additional data publisher

2026-11-10

Timeline

All times UTC

  1. Advisory published

    Publication date supplied by the source.

  2. Source updated

    Latest modification date supplied by the source.

  3. Last imported by cve.new

    Latest catalog import, not the date we first saw this advisory.

What changed

Follow changes
  1. CVE · CVE-2026-123585

    Observed 2026-11-10T18:16:38.352Z · upstream updated 2026-11-10T17:57:43.009Z

    Prioritization updated

    before

    []

    after

    [
  {
    "source": "CISA-ADP",
    "type": "SSVC",
    "role": "CISA Coordinator",
    "timestamp": "2026-11-10T16:29:31.064348Z",
    "decisions": [
      {
        "name": "Exploitation",
        "value": "none"
      },
      {
        "name": "Automatable",
        "value": "yes"
      },
      {
        "name": "Technical Impact",
        "value": "partial"
      }
    ]
  }
]

Large field values are marked as truncated previews. Original source snapshots remain retained.

Showing up to 50 most recent observed changes.