CVE-2026-114617 (GCVE-0-2026-114617)

Vulnerability from cvelistv5 – Published: 2026-10-22 21:25 – Updated: 2026-10-23 15:00
VLAI
Title
Authlib: ID token can disable its own nonce validation via the nonce_supported claim
Summary
Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to 1.9.0, OpenIDMixin.parse_id_token() reads the nonce_supported decision from the untrusted ID token being validated and sets the expected nonce to null when that claim is the JSON boolean false. In implicit and hybrid relying parties, or applications that directly accept externally supplied ID tokens, an attacker with a captured validly signed token can bypass the nonce-to-session binding and replay the victim's token into an attacker-controlled session. Plain authorization code flow is not affected, and the token must still pass signature, issuer, and audience validation. OpenIDMixin.parse_id_token() trusts nonce_supported in both authlib/integrations/base_client/sync_openid.py and authlib/integrations/base_client/async_openid.py to disable the expected nonce. This issue is fixed in version 1.9.0.
Severity
4.2 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-10-23 14:48 UTC
CWE
  • CWE-294 - Authentication Bypass by Capture-replay
  • CWE-807 - Reliance on Untrusted Inputs in a Security Decision
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7714 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
authlib authlib Affected: < 1.9.0
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

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