Improper Validation of Integrity Check Value Affecting authlib package, versions [,1.9.0)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PYTHON-AUTHLIB-21460692
- published23 Oct 2026
- disclosed22 Oct 2026
- creditLiyi Zhou, Ziyue Wang, Strick, Maurice, Chenchen Yu
Introduced: 22 Oct 2026
NewCVE-2026-114618 (opens in a new tab)How to fix?
Upgrade authlib to version 1.9.0 or higher.
Overview
authlib is a library in building OAuth and OpenID Connect servers.
Affected versions of this package are vulnerable to Improper Validation of Integrity Check Value via the verify_claims method in JWTBearerGrant, when get_audiences() returns an empty list. Prior to the fix, an unconfigured or default implementation of get_audiences() caused audience validation to be silently skipped, allowing an attacker to present a JWT assertion with an arbitrary or missing aud claim and have it accepted as valid. This enables an attacker with a valid JWT signed by a trusted key to authenticate against an authorization server that has not explicitly configured its audience identifiers, bypassing the audience binding required by RFC 7523.