{"id":"CVE-2026-48990","state":"PUBLISHED","title":"joserfc: b64=false RFC7797 JWS payloads bypass JWSRegistry payload-size limits during deserialization","description":"joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. In versions 1.3.4 through 1.6.5, joserfc accepts oversized RFC7797 b64=false JWS payloads without applying JWSRegistry.max_payload_length, which can lead to resource exhaustion. The normal JWS compact and flattened JSON paths reject payloads above the configured payload-size limit with ExceededSizeError. The RFC7797 unencoded payload paths do not make the same check. A valid b64=false compact or flattened JSON JWS can therefore deserialize successfully with a payload larger than JWSRegistry.max_payload_length. Applications that accept lower-trust JWS values and rely on joserfc to reject oversized token content during verification have a moderate availability risk. This issue has been fixed in version 1.6.7.","publishedAt":"2026-06-17T21:08:10.534Z","updatedAt":"2026-06-18T12:51:59.900Z","severity":{"score":5.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","source":"GitHub_M"},"assigner":"GitHub_M","products":["authlib joserfc"],"affected":[{"vendor":"authlib","product":"joserfc","versions":[{"version":"< 1.6.7","status":"affected"}]}],"references":["https://github.com/authlib/joserfc/security/advisories/GHSA-wphv-vfrh-23q5","https://github.com/authlib/joserfc/releases/tag/1.6.7"],"weaknesses":["CWE-400","CWE-770"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/48xxx/CVE-2026-48990.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-48990","state":"PUBLISHED","datePublished":"2026-06-17T21:08:10.534Z","dateUpdated":"2026-06-18T12:51:59.900Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-05-26T23:26:07.975Z"},"containers":{"cna":{"title":"joserfc: b64=false RFC7797 JWS payloads bypass JWSRegistry payload-size limits during deserialization","descriptions":[{"lang":"en","value":"joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. In versions 1.3.4 through 1.6.5, joserfc accepts oversized RFC7797 b64=false JWS payloads without applying JWSRegistry.max_payload_length, which can lead to resource exhaustion. The normal JWS compact and flattened JSON paths reject payloads above the configured payload-size limit with ExceededSizeError. The RFC7797 unencoded payload paths do not make the same check. A valid b64=false compact or flattened JSON JWS can therefore deserialize successfully with a payload larger than JWSRegistry.max_payload_length. Applications that accept lower-trust JWS values and rely on joserfc to reject oversized token content during verification have a moderate availability risk. This issue has been fixed in version 1.6.7."}],"affected":[{"vendor":"authlib","product":"joserfc","versions":[{"version":"< 1.6.7","status":"affected"}]}],"references":[{"url":"https://github.com/authlib/joserfc/security/advisories/GHSA-wphv-vfrh-23q5","name":"https://github.com/authlib/joserfc/security/advisories/GHSA-wphv-vfrh-23q5","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/authlib/joserfc/releases/tag/1.6.7","name":"https://github.com/authlib/joserfc/releases/tag/1.6.7","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":5.3,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-400","lang":"en","description":"CWE-400: Uncontrolled Resource Consumption","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-770","lang":"en","description":"CWE-770: Allocation of Resources Without Limits or Throttling","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-06-17T21:08:10.534Z"},"source":{"advisory":"GHSA-wphv-vfrh-23q5","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/authlib/joserfc/security/advisories/GHSA-wphv-vfrh-23q5","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-18T12:51:44.745917Z","id":"CVE-2026-48990","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-06-18T12:51:59.900Z"}}]}}}