CVSS 4.0
6.9 mediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:NCVE-2026-123603 Hickory DNS Missing IPv4-Mapped IPv6 Canonicalization Access Control Bypass
Medium (6.9) in hickory-dns hickory-dns. EPSS 0.2% estimated probability of exploitation activity in the next 30 days.
On this page
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.
Severity
CVSS 3.1
6.5 mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N- EPSS
- 0.2% estimated probability of exploitation activity in the next 30 days; 6th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: none · Automatable: yes · Technical impact: partial, assessed 2026-11-13. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- CWE
- CWE-284 Improper Access Control
- OWASP Top 10
- A01:2025 Broken Access Control
- Published
- Modified
- Assigned by
- VulnCheck (CNA)
- NVD analysis
- Deferred: the NVD does not plan to analyze it
- Record from
- the NVD, synced
Ask an AI about this CVE
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Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| hickory-dns | from 0.25.0-alpha.3 through 0.26.0-alpha.1 |
| hickory-dns | from 0.26.0 before 0.26.2 |
| hickory-dns | from 0.25.0-alpha.1 before 0.26.2 |
Fix and patched versions
Linux distributions
| Distribution | Release | Package | Fixed in | Advisory |
|---|---|---|---|---|
| Debian | 13 | rust-hickory-proto, rust-hickory-server, rust-hickory-recursor and 1 more | no fix listed | DEBIAN-CVE-2026-123603 |
| Debian | 14 | rust-hickory-proto, rust-hickory-server, rust-hickory-resolver | 0.26.3-1 | DEBIAN-CVE-2026-123603 |
| Ubuntu | 24.04:LTS | rust-hickory-proto, rust-hickory-resolver | no fix listed | UBUNTU-CVE-2026-123603 |
| Ubuntu | 26.04:LTS, 26.10 | rust-hickory-proto, rust-hickory-server, rust-hickory-recursor and 1 more | no fix listed | UBUNTU-CVE-2026-123603 |
From the distributions' data via OSV.dev: the Debian Security Tracker; Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Debian · Ubuntu.
Attack patterns (CAPEC)
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits. More on the page of CWE-284 (17).
History
- The NVD deferred its analysis
Changes since this site first stored the record. The same for every record: /api/public/changes.