CVE-2026-123603

medium

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.

References

https://www.vulncheck.com/advisories/hickory-dns-missing-ipv4-mapped-ipv6-canonicalization-access-control-bypass

https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-4jwp-xjwm-333g

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-119362

Details

Source: Mitre, NVD

Published: 2026-11-08

Updated: 2026-11-08

Risk Information

CVSS v2

Base Score: 6.4

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:N

Severity: Medium

CVSS v3

Base Score: 6.5

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Severity: Medium

CVSS v4

Base 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

Severity: Medium

EPSS

EPSS: 0.00166