High severity · published Sep 10, 2026
CVE-2026-88861
Capgo AAL1 Session MFA Bypass via Direct RBAC Authorization
8.3
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 44% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CA
capgo.app · Cap-go
0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-88861
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-88861
vendor-advisory
https://github.com/Cap-go/capgo.app/security/advisories/GHSA-9435-5xw9-v29h
third-party-advisory
https://www.vulncheck.com/advisories/capgo-aal1-session-mfa-bypass-via-direct-rbac-authorization
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