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. _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.
History

Tue, 08 Sep 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 07 Sep 2026 08:45:00 +0000

Type Values Removed Values Added
First Time appeared Perl
Perl robots::validate
Vendors & Products Perl
Perl robots::validate

Fri, 04 Sep 2026 15:30:00 +0000

Type Values Removed Values Added
References

Fri, 04 Sep 2026 12:45:00 +0000

Type Values Removed Values Added
Description 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. _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.
Title 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
Weaknesses CWE-405
CWE-770
References

cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published: 2026-09-04T12:21:11.513Z

Updated: 2026-09-08T18:56:35.506Z

Reserved: 2026-08-28T12:56:46.972Z

Link: CVE-2026-82309

cve-icon Vulnrichment

Updated: 2026-09-04T15:07:21.822Z

cve-icon NVD

Status : Deferred

Published: 2026-09-04T13:20:10.667

Modified: 2026-09-08T19:20:00.593

Link: CVE-2026-82309

cve-icon Redhat

No data.