hickory-proto and hickory-resolver 0.26.0 before 0.26.2, hickory-server 0.25.0-alpha.1 before 0.26.2, and hickory-recursor 0.25.0-alpha.3 through 0.26.0-alpha.1 fail to canonicalize IPv4-mapped IPv6 addresses when checking deny_answers, deny_server, or AccessControlSet rules. Attackers can use IPv4-mapped addresses to evade answer filtering, trigger queries to denied nameservers, or reach hickory-server library deployments on dual-stack IPv6 sockets from denied clients.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact Low

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact Low

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
hickory-dns hickory-dns unaffected
Version Status Constraints
0.25.0-alpha.3 affected ≤ 0.26.0-alpha.1
hickory-dns hickory-dns unaffected
Version Status Constraints
0.26.0 affected < 0.26.2
0.26.2 unaffected —
hickory-dns hickory-dns unaffected
Version Status Constraints
0.26.0 affected < 0.26.2
0.26.2 unaffected —
hickory-dns hickory-dns unaffected
Version Status Constraints
0.25.0-alpha.1 affected < 0.26.2
0.26.2 unaffected —

No data.

No data.

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No data.

Project Subscriptions

No data.

Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-4jwp-xjwm-333g cve-icon cve-icon
https://www.vulncheck.com/advisories/hickory-dns-missing-ipv4-mapped-ipv6-canonicalization-access-control-bypass cve-icon cve-icon
History

Sun, 08 Nov 2026 01:45:00 +0000

Type Values Removed Values Added
Description hickory-proto and hickory-resolver 0.26.0 before 0.26.2, hickory-server 0.25.0-alpha.1 before 0.26.2, and hickory-recursor 0.25.0-alpha.3 through 0.26.0-alpha.1 fail to canonicalize IPv4-mapped IPv6 addresses when checking deny_answers, deny_server, or AccessControlSet rules. Attackers can use IPv4-mapped addresses to evade answer filtering, trigger queries to denied nameservers, or reach hickory-server library deployments on dual-stack IPv6 sockets from denied clients.
Title Hickory DNS Missing IPv4-Mapped IPv6 Canonicalization Access Control Bypass
Weaknesses CWE-284
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-11-08T01:38:30.679Z

Reserved: 2026-11-06T01:00:16.506Z

Link: CVE-2026-123603

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-11-08T02:16:55.117

Modified: 2026-11-08T02:16:55.117

Link: CVE-2026-123603

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-11-08T03:15:08Z

Weaknesses