_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.
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Vendor Solution
Upgrade to Robots-Validate 0.3.11 or later.
Tracking
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Tue, 08 Sep 2026 19:30:00 +0000
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cvssV3_1
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Mon, 07 Sep 2026 08:45:00 +0000
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| First Time appeared |
Perl
Perl robots::validate |
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| Vendors & Products |
Perl
Perl robots::validate |
Fri, 04 Sep 2026 15:30:00 +0000
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Fri, 04 Sep 2026 12:45:00 +0000
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| 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 |
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| References |
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Status: PUBLISHED
Assigner: CPANSec
Published:
Updated: 2026-09-08T18:56:35.506Z
Reserved: 2026-08-28T12:56:46.972Z
Link: CVE-2026-82309
Updated: 2026-09-04T15:07:21.822Z
Status : Deferred
Published: 2026-09-04T13:20:10.667
Modified: 2026-09-08T19:20:00.593
Link: CVE-2026-82309
No data.
OpenCVE Enrichment
Updated: 2026-09-10T04:00:06Z