CVE-2026-116672
Description
A flaw was found in Authlib. An authenticated remote attacker can bypass authorization controls to access, modify, or delete configurations belonging to other clients. In deployments implementing the documented reference code for dynamic client configuration, the server validates client editability without confirming that the presented registration access token belongs to the target client. Consequently, an attacker possessing any valid registration token can alter client settings to intercept authorization tokens or delete registrations, causing a denial of service.
Statement
This vulnerability is rated as an Important severity flaw because an authenticated entity holding a valid registration token could modify or delete client registrations belonging to other tenants, compromising OAuth client configurations and potentially intercepting authorization credentials. Within Red Hat environments, Authlib is predominantly utilized for client-side OAuth and OpenID Connect flows rather than hosting Dynamic Client Registration Management endpoints. Consequently, the flaw is only exploitable in environments operating custom OAuth authorization servers that explicitly expose the RFC 7592 client configuration endpoint based on the flawed reference implementation.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.8 | N/A | 8.8 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| 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 | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Access Control
Technical Impact: Bypass Protection Mechanism
Access control checks for specific user data or functionality can be bypassed.
Access Control
Technical Impact: Gain Privileges or Assume Identity
Horizontal escalation of privilege is possible (one user can view/modify information of another user).
Access Control
Technical Impact: Gain Privileges or Assume Identity
Vertical escalation of privilege is possible if the user-controlled key is actually a flag that indicates administrator status, allowing the attacker to gain administrative access.
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