CVE-2026-28490
MEDIUM6.5EPSS 0.02%Authlib Vulnerable to JWE RSA1_5 Bleichenbacher Padding Oracle
Published: 3/16/2026Modified: 5/11/2026
Description
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.
Affected packages (2)
- Debian/python-authlibfrom 0, < 0.15.4-1+deb11u2
- PyPI/authlibfrom 0, < 1.6.9
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N |
| osv | CVSS 3.1 | MEDIUM6.5 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N |
References (6)
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2026-28490
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2026-28490
- PATCHhttps://github.com/authlib/authlib
- WEBhttps://github.com/authlib/authlib/commit/48b345f29f6c459f11c6a40162b6c0b742ef2e22
- WEBhttps://github.com/authlib/authlib/releases/tag/v1.6.9
- WEBhttps://github.com/authlib/authlib/security/advisories/GHSA-7432-952r-cw78