CVE-2026-88864 Capgo SSO Provider Authentication Bypass via PostgREST Direct Write
Attackers with API keys can bypass SSO controls by directly writing to the database, enabling unauthorized SSO enforcement and disrupting logins.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-88864?
CVE-2026-88864 is a critical missing authorization vulnerability in Cap-go capgo.app, published on 10 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Capgo (capgo.app) fails to restrict direct write access to the public.sso_providers table exposed through Supabase PostgREST. A holder of an ordinary Capgo full API key can insert a row with status='active' and enforce_sso=true, bypassing the intended backend SSO provisioning route (supabase/functions/_backend/private/sso/providers.ts) and its controls: the Enterprise plan requirement, SSO provider creation via the Supabase Management API, DNS TXT domain-ownership verification, the pending_verification → verified → active status transition, and issuance of a trusted provider ID by Supabase Auth. The forged row is trusted by SSO discovery and enforcement logic, including the unauthenticated login preflight endpoint /private/sso/check-domain, which then reports {"has_sso": true, "enforce_sso": true} for domains that were never verified, allowing attacker-controlled SSO enforcement to be asserted for arbitrary domains and disrupting normal login. All versions are affected; at the time of the advisory no patch was available.
Weakness: CWE-284
Which versions are affected by CVE-2026-88864?
How do I fix CVE-2026-88864?
No fix has been published for CVE-2026-88864 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-88864 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-88864 exists.
Sources
Also known as GHSA-g597-pqh2-2fw7.