PT-2026-38539 · Crates.Io · Hickory-Net

Published

2026-05-01

·

Updated

2026-05-01

None

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The NSEC3 closest-encloser proof validation in hickory-net's 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 (OOM). A reachable upstream attacker who can return such a response can therefore crash a debug-built validator or exhaust memory on a release-built one.
We recommend all affected users update to hickory-net 0.26.1 for the fix.
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Related Identifiers

RUSTSEC-2026-0120

Affected Products

Hickory-Net