CVE-2026-82309

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.

CVSS v3 4.3 MEDIUM

4.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.8 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact LOW

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/robrwo/Robots-Validate/commit/6426178c49ff6c440922f31a92a6feb3c661b143.patch
https://github.com/robrwo/Robots-Validate/security/advisories/GHSA-6399-5qhh-48h5
https://metacpan.org/release/RRWO/Robots-Validate-v0.4.0/changes
http://www.openwall.com/lists/oss-security/2026/09/04/3

Configurations

No configuration.

History

No history.

Information

Published : 2026-09-04 13:20

Updated : 2026-09-08 19:20

NVD link : CVE-2026-82309

Mitre link : CVE-2026-82309

CVE.ORG link : CVE-2026-82309

JSON object : View

Products Affected

No product.

CWE

CWE-405

Asymmetric Resource Consumption (Amplification)

CWE-770

Allocation of Resources Without Limits or Throttling

{"id": "CVE-2026-82309", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-82309", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-09-08T18:56:08.513256Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 4.3, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "LOW", "confidentialityImpact": "LOW"}, "impactScore": 1.4, "exploitabilityScore": 2.8}]}, "affected": [{"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "affectedData": [{"repo": "https://github.com/robrwo/Robots-Validate", "modules": ["Robots::Validate"], "versions": [{"status": "affected", "version": "0.3.2", "lessThan": "0.3.11", "versionType": "custom"}], "packageURL": "pkg:cpan/Robots-Validate", "packageName": "Robots-Validate", "programFiles": ["lib/Robots/Validate.pm"], "collectionURL": "https://cpan.org/modules", "defaultStatus": "unaffected", "programRoutines": [{"name": "Robots::Validate::_check_dns"}]}]}], "published": "2026-09-04T13:20:10.667", "references": [{"url": "https://github.com/robrwo/Robots-Validate/commit/6426178c49ff6c440922f31a92a6feb3c661b143.patch", "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"}, {"url": "https://github.com/robrwo/Robots-Validate/security/advisories/GHSA-6399-5qhh-48h5", "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"}, {"url": "https://metacpan.org/release/RRWO/Robots-Validate-v0.4.0/changes", "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"}, {"url": "http://www.openwall.com/lists/oss-security/2026/09/04/3", "source": "af854a3a-2127-422b-91ae-364da2661108"}], "vulnStatus": "Deferred", "weaknesses": [{"type": "Secondary", "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "description": [{"lang": "en", "value": "CWE-405"}, {"lang": "en", "value": "CWE-770"}]}], "descriptions": [{"lang": "en", "value": "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.\n\n_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.\n\nAny 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."}], "lastModified": "2026-09-08T19:20:00.593", "sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e"}