Authlib vulnerabilities
We track 16 vulnerabilities in Authlib products across 2 products. 16 are rated high or critical, and none are known to be exploited. The most recent was published on October 29, 2026.
Latest Authlib vulnerabilities
- 7.5 High severity
joserfc: Uncontrolled Resource Consumption
joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to 1.7.5, joserfc.jwe.decrypt_json() accepts a JWE General JSON Serialization recipients array without a count limit and calls dec
- 8.8 High severity
authlib: Authorization Bypass Through User-Controlled Key
Authlib is a Python library which builds OAuth and OpenID Connect servers. From 0.15 until 1.9.1, the documented ClientConfigurationEndpoint.authenticate_client and ClientConfigurationEndpoint.check_permission reference implementations look up a target client
- 9.1 Critical severity
authlib: Improper Authentication
Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to 1.9.1, Authlib's OctKey.import_key() and HMAC signing and verification path accept zero-length key material. If an application's secret lookup can return an empty string or emp
- 9.1 Critical severity
authlib: Incomplete List of Disallowed Inputs
Authlib is a Python library which builds OAuth and OpenID Connect servers. From 1.3.1 until 1.9.0, OctKey.import_key() checks asymmetric-key markers only at byte zero while Authlib's PEM loaders accept leading whitespace, comments, or a byte-order mark. In dep
- 9.1 Critical severity
joserfc: Authentication Bypass by Spoofing
joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to 1.7.4, joserfc.jws.deserialize_json() accepts a JWS General JSON Serialization with an empty signatures array as authenticated.
- 9.8 Critical severity
Authlib: Insufficient Verification of Data Authenticity
Authlib version 1.7.2 and below contains a vulnerability where discovery JSON metadata is cached without validation or issuer-origin binding. This allows a poisoned discovery response to replace all endpoint values with attacker-controlled values rather than e
- 9.8 Critical severity
Authlib (v1.8.0 and below) contains a signature verification bypass vulnerability.
Authlib (v1.8.0 and below) contains a signature verification bypass vulnerability. The JsonWebSignature.deserialize_json() method accepts a JSON Serialization JWS object and returns the payload as successfully verified without checking for a signature and with
- 8.7 High severity
joserfc: Improper Authentication
joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to 1.6.8, joserfc.jwt.decode accepts attacker-forged HMAC-signed tokens when the caller-supplied verification key is the empty str
- 7.5 High severity
authlib: Improper Validation of Integrity Check Value
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 intern
- 9.1 Critical severity
authlib: Improper Verification of Cryptographic Signature
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 verific
- 9.8 Critical severity
authlib: Improper Verification of Cryptographic Signature
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 with
- 7.5 High severity
joserfc: Allocation of Resources Without Limits or Throttling
joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. In 1.6.2 and earlier, a resource exhaustion vulnerability in joserfc allows an unauthenticated attacker to cause a Denial of Service (Do
- 8.8 High severity
authlib: Cross-Site Request Forgery
Authlib is a Python library which builds OAuth and OpenID Connect servers. In versions 1.0.0 through 1.6.5, cache-backed state/request-token storage is not tied to the initiating user session, so CSRF is possible for any attacker that has a valid state (easily
- 7.5 High severity
joserfc: Allocation of Resources Without Limits or Throttling
joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. In versions from 1.3.3 to before 1.3.5 and from 1.4.0 to before 1.4.2, the ExceededSizeError exception messages are embedded with non-de
- 7.5 High severity
Authlib is a Python library which builds OAuth and OpenID Connect servers.
Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.5, Authlib’s JOSE implementation accepts unbounded JWS/JWT header and signature segments. A remote attacker can craft a token whose base64url‑encoded header or sign
- 7.5 High severity
authlib: Insufficient Verification of Data Authenticity
Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.4, Authlib’s JWS verification accepts tokens that declare unknown critical header parameters (crit), violating RFC 7515 “must‑understand” semantics. An attacker can