Auth bypass in Samanhappy Mcphub
CVE-2026-90474
MCPHub before 1.0.32 contains an authentication bypass vulnerability in its embedded OAuth 2.0 authorization server where client authentication is disabled by default and PKCE enforcement is optional. Attackers who obtain an authorization code through interception can redeem it for access tokens without providing a client secret or PKCE verifier, gaining access to victim accounts and their privileges.
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:N/UI:R/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.006 (46.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 46th percentile — 46.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000
Affected products
Weakness classification (CWE)
References
- github.com/samanhappy/mcphub/blob/v1.0.31/src/services/oauthServerService.ts (technical-description)
- github.com/samanhappy/mcphub/commit/e927620cd1a80e8691213b01eb8cd6ffa1a66e9f (patch)
- github.com/samanhappy/mcphub/releases/tag/v1.0.32 (release-notes)
- github.com/samanhappy/mcphub/security/advisories/GHSA-3m7m-37xf-xp9x (vendor-advisory, third-party-advisory)
- www.vulncheck.com/advisories/mcphub-before-1.0.32-oauth-2.0-authentication-bypa… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-90474?
- CVE-2026-90474 is a medium-severity vulnerability in Samanhappy Mcphub, classified under Improper Authentication. CVSS score: 6.8/10. Published 2026-09-12.
- How severe is CVE-2026-90474?
- Medium severity. CVSS v3 base score is 6.8 out of 10.