CVE-2026-107162

MEDIUM 6.8

Express Gateway through 1.16.11 OAuth 2.0 Refresh Token Validation Bypass

CVSS Score

6.8

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-287
Vendor	expressgateway
Product	express-gateway
Published	Oct 7, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N

Attack Vector

Network

Attack Complexity

High

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Affected Versions

ExpressGateway / express-gateway

0 ≤ 1.16.11

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/ExpressGateway/express-gateway/issues/1076 github.com: https://github.com/ExpressGateway/express-gateway github.com: https://github.com/ExpressGateway/express-gateway/blob/45612814d12f65889ef3bdf80b2ed7ab9b557736/lib/policies/oauth2/oauth2-server.js#L221-L247 github.com: https://github.com/ExpressGateway/express-gateway/blob/45612814d12f65889ef3bdf80b2ed7ab9b557736/lib/services/tokens/token.service.js#L100-L136 vulncheck.com: https://www.vulncheck.com/advisories/express-gateway-through-1.16.11-oauth-2.0-refresh-token-validation-bypass

Credits

MD Mahmidul Hasan