Auth bypass in Expressgateway Express-Gateway
CVE-2026-107162
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.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/ExpressGateway/express-gateway/issues/1076 (issue-tracking)
- github.com/ExpressGateway/express-gateway (product)
- github.com/ExpressGateway/express-gateway/blob/45612814d12f65889ef3bdf80b2ed7ab… (technical-description)
- github.com/ExpressGateway/express-gateway/blob/45612814d12f65889ef3bdf80b2ed7ab… (technical-description)
- www.vulncheck.com/advisories/express-gateway-through-1.16.11-oauth-2.0-refresh-… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-107162?
- CVE-2026-107162 is a medium-severity vulnerability in Expressgateway Express-Gateway, classified under Improper Authentication. CVSS score: 6.8/10. Published 2026-10-07.
- How severe is CVE-2026-107162?
- Medium severity. CVSS v3 base score is 6.8 out of 10.