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TI-2026-22754 Aliases CVE-2026-28490GHSA-7432-952r-cw78

Authlib Vulnerable to JWE RSA1_5 Bleichenbacher Padding Oracle

Priority HIGH 69CWE-203Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Attack requirements
Present
Impact type
Information disclosure
Confidentiality · integrity · availability
High · Low · None
Fix status
Partial Red Hat: 4 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-203.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00144 3rd percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial authlib (authlib): 1.6.9authlib (PyPI): 1.6.9Red Hat: 4 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
authlibauthlibbefore 1.6.91.6.9Patch availableCNA
—authlib (PyPI)before 1.6.91.6.9Patch availableGHSA-7432-952r-cw78
  • authlib Vendorauthlib Affected before 1.6.9 Fixed in 1.6.9 Patch available CNA
  • authlib (PyPI) Vendor— Affected before 1.6.9 Fixed in 1.6.9 Patch available GHSA-7432-952r-cw78

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:authlib:authlib:*:*:*:*:*:*:*:*before 1.6.9Vulnerableauthlib
  • cpe:2.3:a:authlib:authlib:*:*:*:*:*:*:*:* Versions before 1.6.9 Vulnerable ·authlib

Remediation

  • Fix · CNA authlib (authlib) Fixed in 1.6.9
  • Fix · GHSA-7432-952r-cw78 authlib (PyPI) Fixed in 1.6.9 Advisory →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Ansible Automation Platform 2AffectedNo fix yet: Fix deferred
Red Hat OpenShift AI (RHOAI)AffectedNo fix yet: Fix deferred
Red Hat Quay 3AffectedNo fix yet: Fix deferred
Red Hat Satellite 6AffectedNo fix yet: Fix deferred
Not affected: 1 product
  • Lightspeed Core

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-28490
  2. 2026-10-03 Alias added: GHSA-7432-952r-cw78

References

Exploit 1

Patch 1

Advisory 1

Other 2

  • TI-2026-22305 Authlib JWS JWK Header Injection: Signature Verification Bypass CVSS 3.1CRITICAL 9.1
  • TI-2026-79518 Authlib fix bypass lets attackers forge HS256 tokens with PEM keys CVSS 3.1CRITICAL 9.1
  • TI-2025-36973 Authlib: JWS/JWT accepts unknown crit headers (RFC violation → possible authz bypass) CVSS 3.1HIGH 7.5
  • TI-2024-25068 lepture Authlib before 1.3.1 has algorithm confusion with asymmetric public keys. CVSS 3.1HIGH 7.5
  • TI-2025-41738 Authlib: 1-click Account Takeover CVSS 3.1HIGH 8.8
  • TI-2026-22761 Authlib: Fail-Open Cryptographic Verification in OIDC Hash Binding CVSS 4.0HIGH 8.2
See all 18 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences