CVE-2026-28490

HIGH EPSS 3.9%
Published Mar 16, 20263mo ago · Modified Jun 17, 20261w ago
8.3 CVSS 4.0
High
Find Similar
Published Mar 16, 2026 3mo ago
Last Modified Jun 17, 2026 1w ago

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.

CVSS Details

Base Score
8.3
Exploitability
—
Impact
—
Vector string
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector Network
Attack Complexity High
Privileges Required None
User Interaction None
Scope X

Threat Intelligence

EPSS Exploit Probability
3.9% percentile
Exploit & Patch Status
Public Exploit Known
Patch Available

Weaknesses 2

CWE-203
CWE-327

Affected Products 1

VendorProductVersionRange
authlibauthlib* <1.6.9

References 3

  • github.com https://github.com/authlib/authlib/commit/48b345f29f6c459f11c6a40162b6c0b742ef2e22
    Patch
  • github.com https://github.com/authlib/authlib/releases/tag/v1.6.9
    ProductRelease Notes
  • github.com https://github.com/authlib/authlib/security/advisories/GHSA-7432-952r-cw78
    ExploitMitigationVendor Advisory

Remediation

  • github.com https://github.com/authlib/authlib/commit/48b345f29f6c459f11c6a40162b6c0b742ef2e22
    Patch