CVE-2026-107162
Awaiting Analysis Awaiting Analysis - Queue

Authentication Bypass in Express Gateway OAuth 2.0

Publication date: 2026-10-07

Last updated on: 2026-10-07

Assigner: VulnCheck

Description
Express Gateway through 1.16.11 contains an authentication bypass vulnerability in the OAuth 2.0 refresh_token grant that fails to validate the token secret or issuing client. Attackers with any valid client credentials and the identifier portion of another user's refresh token can obtain that user's access token and impersonate them against oauth2-protected APIs.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-10-07
Last Modified
2026-10-07
Generated
2026-10-07
AI Q&A
2026-10-07
EPSS Evaluated
N/A
NVD
CVE-2026-107162
EUVD
EUVD-2026-94316

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
ExpressGateway express-gateway 0

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-287 When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

CVE-2026-107162 is an authentication bypass in Express Gateway's OAuth 2.0 refresh token grant. It fails to validate the token secret or issuing client, allowing attackers with valid client credentials and a victim's refresh token ID to obtain the victim's access token and impersonate them against protected APIs.

Detection Guidance

To detect this vulnerability, inspect Express Gateway logs for unusual OAuth 2.0 refresh token requests. Check for requests using only the refresh token identifier without the secret. Monitor for repeated token issuance attempts or access tokens issued to unauthorized clients. Review token.service.js and oauth2-server.js for improper token validation logic.

Impact Analysis

Attackers can impersonate users, access sensitive data, and perform actions on behalf of victims without their knowledge. This requires only network access to the gateway and valid client credentials, making it a high-risk issue for systems using Express Gateway's OAuth 2.0.

Compliance Impact

This vulnerability could lead to unauthorized access to personal or sensitive data, violating GDPR's data protection principles and HIPAA's security requirements. It may result in non-compliance due to potential data breaches and lack of proper access controls.

Mitigation Strategies

Upgrade Express Gateway to a patched version if available. Implement strict token secret validation in refresh token grants. Bind tokens to specific clients and ensure token rotation is enforced. Disable the deletion of tokenDecrypted and add proper error handling for failed validation attempts. Restrict network access to the gateway's OAuth endpoints.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-107162. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart