CVE-2026-123603: medium-severity vulnerability in hickory-dns
Hickory DNS Missing IPv4-Mapped IPv6 Canonicalization Access Control Bypass
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
10Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 6.9
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.
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
Affected products
hickory-dns · hickory-dnsRelated CVEs — hickory-dns
In the same product, most dangerous first.
CVE-2025-25188MEDIUMDNSSEC validation may accept broken authentication chainsEPSS 0.3%CVE-2026-123608HIGHHickory DNS hickory-proto 0.3.1 before 0.26.1 CPU Exhaustion via BinEncoder Name CompressionEPSS —CVE-2026-123607HIGHHickory DNS NSEC3 Closest-Encloser Proof Unbounded Loop Denial of ServiceEPSS —CVE-2026-123606HIGHHickory-DNS Recursor 0.25.0-alpha.3 through 0.25.2 Glueless-NS Referral AmplificationEPSS —CVE-2026-123605HIGHHickory DNS through 0.25.0-alpha.3 DNSSEC Validation Bypass via RRSIG Signer's NameEPSS —CVE-2026-123604HIGHHickory DNS 0.26.0-beta.1 before 0.26.2 Resource Exhaustion DoS via NameServerPool::try_send TC-Retry LoopEPSS —