Robots::Validate versions from 0.3.2 before 0.3.11 for Perl allow unbounded outbound DNS queries per validation via a forward-confirmation loop that does not bound the names it queries

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-82309
StatePUBLISHED
AssignerCPANSec
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-04 13:20:10 UTC
Updated2026-09-04 15:17:35 UTC
DescriptionRobots::Validate versions from 0.3.2 before 0.3.11 for Perl allow unbounded outbound DNS queries per validation via a forward-confirmation loop that does not bound the names it queries. _check_dns issues one PTR query for the client address, keeps the returned names matching the rule's domain, and issues a forward query for each until one resolves back to that address. Nothing bounds that list, and a client controls the reverse zone for its own address, so it chooses how many names the PTR answer holds. Net::DNS refetches a truncated answer over TCP by default, so the 512-byte UDP payload does not cap it either. Any client whose User-Agent matches a rule with a domain reaches _check_dns. Each forward name is distinct and client-chosen, so every query misses the local cache and is resolved against the authoritative servers for that domain. The queries are synchronous, so the caller is held until all of them answer or time out.

Risk And Classification

Problem Types: CWE-405 | CWE-770 | CWE-770 CWE-770 Allocation of Resources Without Limits or Throttling | CWE-405 CWE-405 Asymmetric Resource Consumption (Amplification)

References

ReferenceSourceLinkTags
github.com/robrwo/Robots-Validate/commit/6426178c49ff6c440922f31a92a6feb... 9b29abf9-4ab0-4765-b253-1875cd9b441e github.com
github.com/robrwo/Robots-Validate/security/advisories/GHSA-6399-5qhh-48h5 9b29abf9-4ab0-4765-b253-1875cd9b441e github.com
www.openwall.com/lists/oss-security/2026/09/04/3 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com
metacpan.org/release/RRWO/Robots-Validate-v0.4.0/changes 9b29abf9-4ab0-4765-b253-1875cd9b441e metacpan.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

Solutions

CNA: Upgrade to Robots-Validate 0.3.11 or later.

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