{"id":"CVE-2026-72889","state":"PUBLISHED","title":"Net::OAuth versions before 0.33 for Perl allow the sender to choose the signature algorithm in verify","description":"Net::OAuth versions before 0.33 for Perl allow the sender to choose the signature algorithm in verify.\n\nverify resolves the signature method class from the signature_method parameter of the incoming message. signature_method is required on every request, so the algorithm used to check a signature is chosen by whoever sent it, and nothing lets the verifying party pin the method instead. When a message names HMAC-SHA1 or HMAC-SHA256, the key is derived from consumer_secret and token_secret rather than from the key the provider deployed.\n\nA provider deployed on RSA-SHA1 holds only the consumer public key, and RFC 5849 does not use consumer_secret for that method, so the required parameter is filled with a placeholder. A client that names HMAC-SHA1 instead has its signature checked against that placeholder, so a guessable one is enough to forge requests for any consumer key and token.","publishedAt":"2026-08-19T07:20:09.095Z","updatedAt":"2026-08-26T18:03:05.016Z","severity":{"score":9.8,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"CISA-ADP"},"assigner":"CPANSec","products":["Net-OAuth"],"affected":[{"packageName":"Net-OAuth","packageURL":"pkg:cpan/Net-OAuth","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"0.33","versionType":"custom"}],"collectionURL":"https://cpan.org/modules","modules":["Net::OAuth"],"programFiles":["lib/Net/OAuth/Message.pm","lib/Net/OAuth/Request.pm"],"programRoutines":[{"name":"Net::OAuth::Message::verify"},{"name":"Net::OAuth::Message::_signature_method_class"},{"name":"Net::OAuth::Request::signature_key"}],"repo":"https://github.com/vurtdev/Net-OAuth"}],"references":["https://github.com/vurtdev/Net-OAuth/security/advisories/GHSA-c8rm-g5cm-4pf5","https://github.com/vurtdev/Net-OAuth/commit/c467adf45c8d77ac4b92ad78b3eebf949252ba7f.patch","https://metacpan.org/release/RRWO/Net-OAuth-0.33/changes","https://datatracker.ietf.org/doc/html/rfc5849#section-3.4.2","https://datatracker.ietf.org/doc/html/rfc5849#section-3.4.3","http://www.openwall.com/lists/oss-security/2026/08/19/2"],"weaknesses":["CWE-347","CWE-757"],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/72xxx/CVE-2026-72889.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-72889","state":"PUBLISHED","datePublished":"2026-08-19T07:20:09.095Z","dateUpdated":"2026-08-26T18:03:05.016Z","assignerShortName":"CPANSec","assignerOrgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","dateReserved":"2026-08-10T15:44:58.172Z"},"containers":{"cna":{"title":"Net::OAuth versions before 0.33 for Perl allow the sender to choose the signature algorithm in verify","descriptions":[{"lang":"en","value":"Net::OAuth versions before 0.33 for Perl allow the sender to choose the signature algorithm in verify.\n\nverify resolves the signature method class from the signature_method parameter of the incoming message. signature_method is required on every request, so the algorithm used to check a signature is chosen by whoever sent it, and nothing lets the verifying party pin the method instead. When a message names HMAC-SHA1 or HMAC-SHA256, the key is derived from consumer_secret and token_secret rather than from the key the provider deployed.\n\nA provider deployed on RSA-SHA1 holds only the consumer public key, and RFC 5849 does not use consumer_secret for that method, so the required parameter is filled with a placeholder. A client that names HMAC-SHA1 instead has its signature checked against that placeholder, so a guessable one is enough to forge requests for any consumer key and token."}],"affected":[{"packageName":"Net-OAuth","packageURL":"pkg:cpan/Net-OAuth","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"0.33","versionType":"custom"}],"collectionURL":"https://cpan.org/modules","modules":["Net::OAuth"],"programFiles":["lib/Net/OAuth/Message.pm","lib/Net/OAuth/Request.pm"],"programRoutines":[{"name":"Net::OAuth::Message::verify"},{"name":"Net::OAuth::Message::_signature_method_class"},{"name":"Net::OAuth::Request::signature_key"}],"repo":"https://github.com/vurtdev/Net-OAuth"}],"references":[{"url":"https://github.com/vurtdev/Net-OAuth/security/advisories/GHSA-c8rm-g5cm-4pf5","tags":["vendor-advisory"]},{"url":"https://github.com/vurtdev/Net-OAuth/commit/c467adf45c8d77ac4b92ad78b3eebf949252ba7f.patch","tags":["patch"]},{"url":"https://metacpan.org/release/RRWO/Net-OAuth-0.33/changes","tags":["release-notes"]},{"url":"https://datatracker.ietf.org/doc/html/rfc5849#section-3.4.2","tags":["technical-description"]},{"url":"https://datatracker.ietf.org/doc/html/rfc5849#section-3.4.3","tags":["technical-description"]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-347","description":"CWE-347 Improper Verification of Cryptographic Signature","lang":"en","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-757","description":"CWE-757 Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade')","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"CPANSec","orgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","dateUpdated":"2026-08-19T07:20:09.095Z"},"solutions":[{"lang":"en","value":"Upgrade to Net-OAuth 0.33 or later."}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"cpansec-cna-tool 0.1"}},"adp":[{"title":"CVE Program Container","references":[{"url":"http://www.openwall.com/lists/oss-security/2026/08/19/2"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2026-08-19T21:07:38.218Z"}},{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":9.8,"attackVector":"NETWORK","baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","integrityImpact":"HIGH","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"NONE","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-08-26T18:02:49.745063Z","id":"CVE-2026-72889","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-26T18:03:05.016Z"}}]}}}