CVE-2026-123603
Hickory DNS Missing IPv4-Mapped IPv6 Canonicalization Access Control Bypass
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-284 |
| Vendor | hickory-dns |
| Product | hickory-dns |
| Published | Nov 8, 2026 |
Stay Ahead of the Next One
Get instant alerts for hickory-dns hickory-dns
Be the first to know when new medium vulnerabilities affecting hickory-dns hickory-dns are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None
Affected Versions
hickory-dns / hickory-dns
0.25.0-alpha.3 ≤ 0.26.0-alpha.1
hickory-dns / hickory-dns
0.26.0 < 0.26.2
hickory-dns / hickory-dns
0.26.0 < 0.26.2
hickory-dns / hickory-dns
0.25.0-alpha.1 < 0.26.2
References
Credits
🔍 qifan-sailboat