CVE-2026-88861
Capgo AAL1 Session MFA Bypass via Direct RBAC Authorization
- State
- Published
- Severity
- 8.7 High
- Published
- Sep 10, 2026
- Updated
- Sep 30, 2026
- Reserved
- Sep 10, 2026
Description
Capgo (Cap-go/capgo.app) contains an authentication bypass affecting all versions (no patched version available at time of publication). The Edge authorization path allows a password-only Supabase aal1 session to exercise privileged RBAC permissions even when the account has a verified MFA factor that has not been used for the session: the Edge JWT middleware (foundJWT() in supabase/functions/_backend/utils/hono_middleware.ts) accepts the JWT without validating its assurance level, and the direct RBAC path (checkPermission()/checkPermissionPg() in supabase/functions/_backend/utils/rbac.ts calling public.rbac_check_permission_direct()) authorizes by user ID without passing or checking the session aal, unlike the public.verify_mfa() control which correctly requires aal2. An attacker who knows only the victim's password can therefore authenticate, mint a persistent app-scoped app_admin API key that remains valid after the aal1 session is logged out, and perform privileged operations such as modifying production OTA channel configurations (validated by changing a public production channel from bundle 1.0.0 to 1.0.1), defeating the protection provided by MFA.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.7 High | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 8.3 High | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L | VulnCheck |
Weaknesses
- CWE-288 Authentication Bypass Using an Alternate Path or Channel
Affected Products
| Product | Versions |
|---|---|
capgo.appCap-go |
|
References
- GitHub Security Advisory (GHSA-9435-5xw9-v29h)vendor-advisory
- VulnCheck Advisory: Capgo AAL1 Session MFA Bypass via Direct RBAC Authorizationthird-party-advisory
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