GHSA-3V94-MW7P-V465
Vulnerability from github – Published: 2026-05-07 02:59 – Updated: 2026-05-07 02:59The NSEC3 closest-encloser proof validation in hickory-proto's (0.25.0-alpha.3 ... 0.25.2) and hickory-net's (0.26.0-alpha.1 .. 0.26.0) DnssecDnsHandle walks from the QNAME up to the SOA owner name, building a list of candidate encloser names. The iterator used assumes the QNAME is a descendant of the SOA owner, terminating only when the current candidate equals the SOA name. When the SOA in a response's authority section is not an ancestor of the QNAME, the loop stalls at the DNS root and never terminates, repeatedly calling Name::base_name() and pushing newly allocated Name and hashed-name entries into the candidate Vec.
The bug is reachable by any caller of DnssecDnsHandle, including the resolver, recursor, and client, when built with the dnssec-ring or dnssec-aws-lc-rs feature and configured to perform DNSSEC validation. It is triggered while validating a NoData or NXDomain response whose authority section contains an SOA record from a zone other than an ancestor of the QNAME, on a code path that requires NSEC3 closest-encloser proof. In practice this can be reached through an insecure CNAME chain that crosses zone boundaries into a DNSSEC-signed zone returning NoData, but the minimum condition is just a mismatched SOA owner on a response requiring NSEC3 validation.
A debug_assert_ne!(name, Name::root()) guards the loop body, so debug builds abort with a panic on the first iteration past the root. Release builds compile the assertion out and run the loop unbounded, allocating until the process exhausts available memory. A reachable upstream attacker who can return such a response can therefore crash a debug build or exhaust memory on a release build, for the affected configurations.
The affected code was migrated from hickory-proto to hickory-net as part of the 0.26.0 release. Hickory DNS recommends that all affected users update to hickory-net 0.26.1 for the fix.
Reporter
David Cook, ISRG
{
"affected": [
{
"package": {
"ecosystem": "crates.io",
"name": "hickory-proto"
},
"ranges": [
{
"events": [
{
"introduced": "0.25.0-alpha.3"
},
{
"last_affected": "0.25.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 0.26.0"
},
"package": {
"ecosystem": "crates.io",
"name": "hickory-net"
},
"ranges": [
{
"events": [
{
"introduced": "0.26.0-alpha.1"
},
{
"fixed": "0.26.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [],
"database_specific": {
"cwe_ids": [
"CWE-835"
],
"github_reviewed": true,
"github_reviewed_at": "2026-05-07T02:59:20Z",
"nvd_published_at": null,
"severity": "HIGH"
},
"details": "The NSEC3 closest-encloser proof validation in `hickory-proto`\u0027s (0.25.0-alpha.3 ... 0.25.2) and `hickory-net`\u0027s (0.26.0-alpha.1 .. 0.26.0) `DnssecDnsHandle` walks from the QNAME up to the SOA owner name, building a list of candidate encloser names. The iterator used assumes the QNAME is a descendant of the SOA owner, terminating only when the current candidate equals the SOA name. When the SOA in a response\u0027s authority section is not an ancestor of the QNAME, the loop stalls at the DNS root and never terminates, repeatedly calling `Name::base_name()` and pushing newly allocated `Name` and hashed-name entries into the candidate `Vec`.\n\nThe bug is reachable by any caller of `DnssecDnsHandle`, including the resolver, recursor, and client, when built with the `dnssec-ring` or `dnssec-aws-lc-rs` feature and configured to perform DNSSEC validation. It is triggered while validating a NoData or NXDomain response whose authority section contains an SOA record from a zone other than an ancestor of the QNAME, on a code path that requires NSEC3 closest-encloser proof. In practice this can be reached through an insecure CNAME chain that crosses zone boundaries into a DNSSEC-signed zone returning NoData, but the minimum condition is just a mismatched SOA owner on a response requiring NSEC3 validation.\n\nA `debug_assert_ne!(name, Name::root())` guards the loop body, so debug builds abort with a panic on the first iteration past the root. Release builds compile the assertion out and run the loop unbounded, allocating until the process exhausts available memory. A reachable upstream attacker who can return such a response can therefore crash a debug build or exhaust memory on a release build, for the affected configurations.\n\nThe affected code was migrated from `hickory-proto` to `hickory-net` as part of the 0.26.0 release. Hickory DNS recommends that all affected users update to `hickory-net` 0.26.1 for the fix.\n\n### Reporter\n\nDavid Cook, ISRG",
"id": "GHSA-3v94-mw7p-v465",
"modified": "2026-05-07T02:59:20Z",
"published": "2026-05-07T02:59:20Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-3v94-mw7p-v465"
},
{
"type": "PACKAGE",
"url": "https://github.com/hickory-dns/hickory-dns"
},
{
"type": "WEB",
"url": "https://rustsec.org/advisories/RUSTSEC-2026-0118.html"
},
{
"type": "WEB",
"url": "https://rustsec.org/advisories/RUSTSEC-2026-0120.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "hickory-proto: NSEC3 closest-encloser proof validation enters unbounded loop on cross-zone responses"
}
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