Vulnerability in Cap-Go Capgo.app
CVE-2026-88861
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.3 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L.
EPSS exploit prediction
EPSS: 0.005 (43.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 44th percentile — 43.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/Cap-go/capgo.app/security/advisories/GHSA-9435-5xw9-v29h (vendor-advisory)
- www.vulncheck.com/advisories/capgo-aal1-session-mfa-bypass-via-direct-rbac-auth… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-88861?
- CVE-2026-88861 is a high-severity vulnerability in Cap-Go Capgo.app, classified under Authentication Bypass Using an Alternate Path or Channel. CVSS score: 8.3/10. Published 2026-09-10.
- How severe is CVE-2026-88861?
- High severity. CVSS v3 base score is 8.3 out of 10.
- Is CVE-2026-88861 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.