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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| hickory-dns | hickory-dns | 0.25.0-alpha.3 – ≤ 0.26.0-alpha.1, 0.26.0 – < 0.26.2, 0.25.0-alpha.1 – < 0.26.2 | 0.26.2 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | rust-hickory-proto +2 | 0.26.3-1 | — |
| Debian 13 | rust-hickory-proto +3 | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | rust-hickory-proto +3 | No fix yet | — |
| Ubuntu 26.04 LTS | rust-hickory-proto +3 | No fix yet | — |
| Ubuntu 24.04 LTS | rust-hickory-proto +1 | No fix yet | — |
References
- GitHub Security Advisory (GHSA-4jwp-xjwm-333g) vendor-advisory
- VulnCheck Advisory: Hickory DNS Missing IPv4-Mapped IPv6 Canonicalization Access Control Bypass third-party-advisory