Description
The DNS wire-format message parser in hickory-proto (Hickory DNS) 0.18 before 0.26.2 preallocates record vectors sized by the untrusted ANCOUNT, NSCOUNT, and ARCOUNT header fields before reading record data. Remote attackers can send a UDP datagram, or a spoofed response to a client/resolver, with these counts set to 65535, forcing about 18MB of allocation per message.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| hickory-dns | hickory-dns | 0.18 – < 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 | 0.26.3-1 | — |
| Debian 13 | rust-hickory-proto | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | rust-hickory-proto | No fix yet | — |
| Ubuntu 26.04 LTS | rust-hickory-proto | No fix yet | — |
| Ubuntu 24.04 LTS | rust-hickory-proto | No fix yet | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | netavark | No fix yet | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| crates.io | hickory-proto | >= 0.18.0, < 0.26.2 | 0.26.2 | RUSTSEC-2026-0491 |
References
- GitHub Security Advisory (GHSA-67wc-6jq8-ghrc) vendor-advisory
- VulnCheck Advisory: Hickory DNS from 0.18 before 0.26.2 Memory Amplification DoS via RR Counts third-party-advisory