{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "joserfc",
          "vendor": "authlib",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.7.3"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to version 1.7.3, JWTClaimsRegistry applies membership matching to list-valued iss and sub claims, allowing an array-valued iss that contains the expected issuer to pass an intended equality check and enabling issuer-validation bypass. This issue is fixed in version 1.7.3."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 6.5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-290",
              "description": "CWE-290: Authentication Bypass by Spoofing",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-345",
              "description": "CWE-345: Insufficient Verification of Data Authenticity",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-24T20:08:07.088Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/authlib/joserfc/security/advisories/GHSA-r74j-q665-7rpj",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/authlib/joserfc/security/advisories/GHSA-r74j-q665-7rpj"
        },
        {
          "name": "https://github.com/authlib/joserfc/commit/76ee6a59bf5773c0af00b99076c5e199031f97f1",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/authlib/joserfc/commit/76ee6a59bf5773c0af00b99076c5e199031f97f1"
        }
      ],
      "source": {
        "advisory": "GHSA-r74j-q665-7rpj",
        "discovery": "UNKNOWN"
      },
      "title": "joserfc claim-validation bypass via array-typed single-string claims (iss/sub/jti)"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-75509",
    "datePublished": "2026-08-24T20:08:07.088Z",
    "dateReserved": "2026-08-17T20:49:21.598Z",
    "dateUpdated": "2026-08-24T20:08:07.088Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-75509\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-08-24T20:17:19.183\",\"lastModified\":\"2026-08-24T20:17:19.183\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to version 1.7.3, JWTClaimsRegistry applies membership matching to list-valued iss and sub claims, allowing an array-valued iss that contains the expected issuer to pass an intended equality check and enabling issuer-validation bypass. This issue is fixed in version 1.7.3.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"authlib\",\"product\":\"joserfc\",\"versions\":[{\"version\":\"\u003c 1.7.3\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N\",\"baseScore\":6.5,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"LOW\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":2.2,\"impactScore\":4.2}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-290\"},{\"lang\":\"en\",\"value\":\"CWE-345\"}]}],\"references\":[{\"url\":\"https://github.com/authlib/joserfc/commit/76ee6a59bf5773c0af00b99076c5e199031f97f1\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/authlib/joserfc/security/advisories/GHSA-r74j-q665-7rpj\",\"source\":\"security-advisories@github.com\"}]}}"
  }
}