CVE-2026-107162

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.

References

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