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DEBIAN-CVE-2026-28498

Type: advisorySource: OSV1 source record

Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.9, a library-level vulnerability was identified in the Authlib Python library concerning the validation of OpenID Connect (OIDC) ID Tokens. Specifically, the internal hash verification logic (_verify_hash) responsible for validating the at_hash (Access Token Hash) and c_hash (Authorization Code Hash) claims exhibits a fail-open behavior when encountering an unsupported or unknown cryptographic algorithm. This flaw allows an attacker to bypass mandatory integrity protections by supplying a forged ID Token with a deliberately unrecognized alg header parameter. The library intercepts the unsupported state and silently returns True (validation passed), inherently violating fundamental cryptographic design principles and direct OIDC specifications. This issue has been patched in version 1.6.9.

Announced Source revision 1
Original source ↗

DEBIAN-CVE-2026-28498

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: osv:DEBIAN-CVE-2026-28498

python-authlib

Source reference: /affected/0/package/name

Affected versions
1.2.0-1

Source reference: /affected/0/versions

1.2.0-1+deb12u1

Source reference: /affected/0/versions

Fixed versions
1.2.0-1+deb12u2

Source reference: /affected/0/ranges

Prerequisites
Not stated in this record

python-authlib

Source reference: /affected/1/package/name

Affected versions
1.6.0-1

Source reference: /affected/1/versions

1.6.0-1+deb13u1

Source reference: /affected/1/versions

1.6.1-1

Source reference: /affected/1/versions

1.6.3-1

Source reference: /affected/1/versions

1.6.4-1

Source reference: /affected/1/versions

1.6.5-1

Source reference: /affected/1/versions

1.6.6-1

Source reference: /affected/1/versions

1.6.7-1

Source reference: /affected/1/versions

1.6.8-1

Source reference: /affected/1/versions

1.6.9-1

Source reference: /affected/1/versions

1.7.0-1

Source reference: /affected/1/versions

1.7.2-1

Source reference: /affected/1/versions

1.7.2-2

Source reference: /affected/1/versions

Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

python-authlib

Source reference: /affected/2/package/name

Affected versions
1.6.0-1

Source reference: /affected/2/versions

1.6.1-1

Source reference: /affected/2/versions

1.6.3-1

Source reference: /affected/2/versions

1.6.4-1

Source reference: /affected/2/versions

1.6.5-1

Source reference: /affected/2/versions

1.6.6-1

Source reference: /affected/2/versions

1.6.7-1

Source reference: /affected/2/versions

1.6.8-1

Source reference: /affected/2/versions

Fixed versions
1.6.9-1

Source reference: /affected/2/ranges

Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "1.2.0-1+deb12u2"
          }
        ]
      }
    ],
    "package": {
      "name": "python-authlib",
      "purl": "pkg:deb/debian/python-authlib?arch=source&distro=bookworm",
      "ecosystem": "Debian:12"
    },
    "versions": [
      "1.2.0-1",
      "1.2.0-1+deb12u1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-28498.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          }
        ]
      }
    ],
    "package": {
      "name": "python-authlib",
      "purl": "pkg:deb/debian/python-authlib?arch=source&distro=trixie",
      "ecosystem": "Debian:13"
    },
    "versions": [
      "1.6.0-1",
      "1.6.0-1+deb13u1",
      "1.6.1-1",
      "1.6.3-1",
      "1.6.4-1",
      "1.6.5-1",
      "1.6.6-1",
      "1.6.7-1",
      "1.6.8-1",
      "1.6.9-1",
      "1.7.0-1",
      "1.7.2-1",
      "1.7.2-2"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-28498.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "1.6.9-1"
          }
        ]
      }
    ],
    "package": {
      "name": "python-authlib",
      "purl": "pkg:deb/debian/python-authlib?arch=source&distro=forky",
      "ecosystem": "Debian:14"
    },
    "versions": [
      "1.6.0-1",
      "1.6.1-1",
      "1.6.3-1",
      "1.6.4-1",
      "1.6.5-1",
      "1.6.6-1",
      "1.6.7-1",
      "1.6.8-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-28498.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  }
]

Publisher severity

No explicit severity was provided.

Event
#56695 · Revision 1
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Publisher date
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