CVE-2026-28490 — Authlib Vulnerable to JWE RSA1_5 Bleichenbacher Padding Oracle
Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.9, a cryptographic padding oracle vulnerability was identified in the Authlib Pyt…
Published: 2026-03-16 · CVSS: 8.3 · CVSS 4.0
Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.9, a cryptographic padding oracle vulnerability was identified in the Authlib Python library concerning the implementation of the JSON Web Encryption (JWE) RSA1_5 key management algorithm. Authlib registers RSA1_5 in its default algorithm registry without requiring explicit opt-in, and actively destroys the constant-time Bleichenbacher mitigation that the underlying cryptography library implements correctly. This issue has been patched in version 1.6.9.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7