Authentication Bypass Affecting python-authlib package, versions *


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.23% (14th percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-PYTHONAUTHLIB-21603139
  • published23 Oct 2026
  • disclosed22 Oct 2026

Introduced: 22 Oct 2026

NewCVE-2026-114617  (opens in a new tab)
CWE-294  (opens in a new tab)
CWE-807  (opens in a new tab)

How to fix?

There is no fixed version for Debian:unstable python-authlib.

NVD Description

Note: Versions mentioned in the description apply only to the upstream python-authlib package and not the python-authlib package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1