CVE catalog

CVE-2026-27962

Authlib is a Python library which builds OAuth and…

Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.9, a JWK Header Injection vulnerability in authlib's JWS implementation allows an unauthenticated attacker to forge arbitrary JWT tokens that pass signature verification. When key=None is passed to any JWS deserialization function, the library extracts and uses the cryptographic key embedded in the attacker-controlled JWT jwk header field. An attacker can sign a token with their own private key, embed the matching public key in the header, and have the server accept the forged token as cryptographically valid — bypassing authentication and authorization entirely. This issue has been patched in version 1.6.9.

Severity: Critical · CVSS 9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Published: Mar 16, 2026, 5:34:38 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.56% · Oct 27, 2026

Projects and upstream resources

[python-authlib][Source-reported homepage]

Reported versions and fixes

Each observation applies to its named package, distribution, and release. Distribution backports can fix a vulnerability while retaining an older upstream version number.

Version impact has not been established. The original provider fields are retained below.

Provider details and historical evidence

Original provider fields

{
  "package_releases": [
    {
      "name": "python-authlib",
      "status": "fixed",
      "release": "sid",
      "version": "1.9.1-1"
    },
    {
      "name": "python-authlib",
      "status": "fixed",
      "release": "forky",
      "version": "1.7.2-2"
    },
    {
      "name": "python-authlib",
      "status": "vulnerable",
      "release": "trixie",
      "version": "1.6.0-1+deb13u1"
    },
    {
      "name": "python-authlib",
      "status": "vulnerable",
      "release": "bookworm",
      "version": "1.2.0-1+deb12u1"
    },
    {
      "name": "python-authlib",
      "status": "fixed",
      "release": "bookworm-security",
      "version": "1.2.0-1+deb12u2"
    }
  ],
  "fixed_versions": [
    {
      "bug": null,
      "name": "python-authlib",
      "type": "source",
      "origin": null,
      "release": "sid",
      "urgency": "not yet assigned",
      "fixed_version": "1.6.9-1"
    },
    {
      "bug": null,
      "name": "python-authlib",
      "type": "source",
      "origin": null,
      "release": "forky",
      "urgency": "not yet assigned",
      "fixed_version": "1.6.9-1"
    },
    {
      "bug": null,
      "name": "python-authlib",
      "type": "source",
      "origin": null,
      "release": "trixie",
      "urgency": "not yet assigned",
      "fixed_version": ""
    },
    {
      "bug": null,
      "name": "python-authlib",
      "type": "source",
      "origin": null,
      "release": "bookworm",
      "urgency": "not yet assigned",
      "fixed_version": "1.2.0-1+deb12u2"
    }
  ],
  "distribution_packages": [
    {
      "name": "authlib",
      "ecosystem": "pip",
      "fixed_version": "1.6.9"
    },
    {
      "name": "python-authlib",
      "ecosystem": "cpe",
      "fixed_version": "not yet fixed"
    },
    {
      "name": "python-authlib",
      "ecosystem": "cpe",
      "fixed_version": "1.3.0-1ubuntu0.1~esm2"
    },
    {
      "name": "python-authlib-doc",
      "ecosystem": "cpe",
      "fixed_version": "1.3.0-1ubuntu0.1~esm2"
    },
    {
      "name": "python3-authlib",
      "ecosystem": "cpe",
      "fixed_version": "1.3.0-1ubuntu0.1~esm2"
    },
    {
      "name": "authlib",
      "ranges": [
        {
          "fixed": "1.6.9",
          "introduced": "",
          "last_affected": "",
          "start_excluding": ""
        }
      ],
      "ecosystem": "cpe",
      "fixed_version": "1.6.9",
      "provider_record_id": "NVD-CVE-2026-27962"
    },
    {
      "name": "python-authlib",
      "distro": "ubuntu",
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.6.7-1ubuntu0.1~esm1"
            }
          ]
        }
      ],
      "release": "pro",
      "versions": [
        "1.6.0-1",
        "1.6.5-1",
        "1.6.6-1",
        "1.6.7-1"
      ],
      "ecosystem": "deb",
      "fixed_version": "1.6.7-1ubuntu0.1~esm1",
      "provider_record_id": "USN-8557-1"
    },
    {
      "name": "python-Authlib",
      "distro": "opensuse",
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.5.2-bp160.3.1"
            }
          ]
        }
      ],
      "release": "leap 16.0",
      "versions": [],
      "ecosystem": "rpm",
      "fixed_version": "1.5.2-bp160.3.1",
      "provider_record_id": "OPENSUSE-SU-2026:20392-1"
    },
    {
      "name": "python-Authlib",
      "distro": "suse",
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.3.1-150600.3.17.1"
            }
          ]
        }
      ],
      "release": "linux enterprise module for python 3 15 sp7",
      "versions": [],
      "ecosystem": "rpm",
      "fixed_version": "1.3.1-150600.3.17.1",
      "provider_record_id": "SUSE-SU-2026:0975-1"
    },
    {
      "name": "python-Authlib",
      "distro": "suse",
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.3.1-150600.3.17.1"
            }
          ]
        }
      ],
      "release": "linux enterprise server 15 sp6-ltss",
      "versions": [],
      "ecosystem": "rpm",
      "fixed_version": "1.3.1-150600.3.17.1",
      "provider_record_id": "SUSE-SU-2026:0975-1"
    },
    {
      "name": "python-Authlib",
      "distro": "suse",
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.3.1-150600.3.17.1"
            }
          ]
        }
      ],
      "release": "linux enterprise server for sap applications 15 sp6",
      "versions": [],
      "ecosystem": "rpm",
      "fixed_version": "1.3.1-150600.3.17.1",
      "provider_record_id": "SUSE-SU-2026:0975-1"
    },
    {
      "name": "python-Authlib",
      "distro": "opensuse",
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.3.1-150600.3.17.1"
            }
          ]
        }
      ],
      "release": "leap 15.6",
      "versions": [],
      "ecosystem": "rpm",
      "fixed_version": "1.3.1-150600.3.17.1",
      "provider_record_id": "SUSE-SU-2026:0975-1"
    }
  ]
}

OpenFactory catalog packages

Matching against OpenFactory catalog package versions is in progress.

[Debian 12 (Bookworm)]

[python3-authlib]Unknown
Source package: [python-authlib]
Details (4)
- 1.2.0-1+deb12u1 · all · bookworm
  Affected · Fixed: 1.2.0-1+deb12u2
  nvd · python-authlib · debian · bookworm; nvd · python-authlib · debian · 12
- 1.2.0-1+deb12u1 · all · bookworm
  Affected · Fixed: 1.2.0-1+deb12u2
  nvd · python-authlib · debian · bookworm; nvd · python-authlib · debian · 12
- 1.2.0-1+deb12u2 · all · bookworm-security
  Fixed · Fixed: 1.2.0-1+deb12u2
  nvd · python-authlib · debian · bookworm; nvd · python-authlib · debian · 12
- 1.2.0-1+deb12u2 · all · bookworm-security
  Fixed · Fixed: 1.2.0-1+deb12u2
  nvd · python-authlib · debian · bookworm; nvd · python-authlib · debian · 12
[python-authlib-doc]Unknown
Source package: [python-authlib]
Details (4)
- 1.2.0-1+deb12u1 · all · bookworm
  Affected · Fixed: 1.2.0-1+deb12u2
  nvd · python-authlib · debian · bookworm; nvd · python-authlib · debian · 12
- 1.2.0-1+deb12u1 · all · bookworm
  Affected · Fixed: 1.2.0-1+deb12u2
  nvd · python-authlib · debian · bookworm; nvd · python-authlib · debian · 12
- 1.2.0-1+deb12u2 · all · bookworm-security
  Fixed · Fixed: 1.2.0-1+deb12u2
  nvd · python-authlib · debian · bookworm; nvd · python-authlib · debian · 12
- 1.2.0-1+deb12u2 · all · bookworm-security
  Fixed · Fixed: 1.2.0-1+deb12u2
  nvd · python-authlib · debian · bookworm; nvd · python-authlib · debian · 12

[Debian 13 (Trixie)]

[python3-authlib]Unknown
Source package: [python-authlib]
Details (2)
- 1.6.0-1+deb13u1 · all · trixie
  Affected
  nvd · python-authlib · debian · 13
- 1.6.0-1+deb13u1 · all · trixie
  Affected
  nvd · python-authlib · debian · 13
[python-authlib-doc]Unknown
Source package: [python-authlib]
Details (2)
- 1.6.0-1+deb13u1 · all · trixie
  Affected
  nvd · python-authlib · debian · 13
- 1.6.0-1+deb13u1 · all · trixie
  Affected
  nvd · python-authlib · debian · 13

Observed: Oct 23, 2026, 10:42:05 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [GitHub Advisory Database] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX] · [Ubuntu Security Notices (USN)]