CVE-2026-114618
Description
A flaw was found in Authlib. In the default JSON Web Token (JWT) bearer grant implementation, audience claims are checked only for existence rather than validated against the target authorization server. A remote attacker holding a legitimate token issued for another service can present it to a server sharing the same signing key to obtain an unauthorized access token. This allows attackers to bypass trust boundaries and gain unauthorized access to protected resources.
Statement
This vulnerability is rated as Moderate because successful exploitation requires specific environmental preconditions, including an existing authenticated assertion issued by a shared identity authority. Applications deploying Authlib as an authorization server are only exposed if they implement RFC 7523 JWT bearer grants using the default validation logic. Deployments where services maintain distinct cryptographic signing keys or enforce explicit audience filtering within their token verification workflows remain unaffected.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.8 | N/A | 6.8 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
