CVE-2026-50631

Modified Modified - Updated After Analysis

Race Condition in AbstractOAuthDataProvider Allows Token Reuse

Publication date: 2026-06-12

Last updated on: 2026-08-07

Assigner: Apache Software Foundation

Description

A race condition in AbstractOAuthDataProvider allows concurrent requests using the same Refresh Token to bypass single-use semantics and generate multiple valid Access Tokens, when 'recycleRefreshTokens' is set to false. A leaked refresh token can be replayed concurrently by multiple attackers or threads. Users are recommended to upgrade to versions 4.2.2 or 4.1.7 or 3.6.12, which fixes this issue.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-06-12

Last Modified

2026-08-07

Generated

2026-08-11

AI Q&A

2026-06-12

EPSS Evaluated

2026-08-10

NVD

CVE-2026-50631

EUVD

EUVD-2026-36399

Affected Vendors & Products

Vendor	Product	Version / Range
apache	cxf	to 4.1.7 (exc)
apache	cxf	From 4.2.0 (inc) to 4.2.2 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-367	The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.

Attack-Flow Graph

Executive Summary

This vulnerability is a race condition in Apache CXF's OAuth2 implementation, specifically in the AbstractOAuthDataProvider component.

It occurs when concurrent requests use the same refresh token while the 'recycleRefreshTokens' setting is set to false, allowing these requests to bypass the intended single-use restriction on refresh tokens.

As a result, multiple valid access tokens can be generated from the same refresh token simultaneously.

Attackers who have obtained a leaked refresh token can exploit this by replaying it concurrently through multiple threads or requests.

The issue affects Apache CXF versions before 4.2.2 and before 4.1.7, and upgrading to these fixed versions is recommended.

Detection Guidance

There is no specific information provided about detection methods or commands to identify this vulnerability on your network or system.

Impact Analysis

This vulnerability can impact you by allowing attackers to generate multiple valid access tokens from a single leaked refresh token.

This undermines the security model that assumes refresh tokens are single-use, potentially leading to unauthorized access to protected resources.

If exploited, it could result in multiple attackers or processes gaining simultaneous access, increasing the risk of data breaches or unauthorized actions.

Compliance Impact

The provided information does not specify how this vulnerability affects compliance with common standards and regulations such as GDPR or HIPAA.

Mitigation Strategies

To mitigate this vulnerability, users are recommended to upgrade Apache CXF to versions 4.2.2 or 4.1.7, which contain fixes for this issue.

This upgrade prevents the race condition in AbstractOAuthDataProvider that allows concurrent requests using the same refresh token to bypass single-use semantics and generate multiple valid access tokens.

Hi! I’m here to help you understand CVE-2026-50631. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70