# 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.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Sep 2026
- **Updated:** 30 Sep 2026
- **Also known as:** GHSA-g597-pqh2-2fw7

## 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 (Improper Access Control)

## 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.

## Is CVE-2026-88864 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-88864 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-88864 and fix it if it is affected.

What it is: 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-88864 exists.

Affected product: Cap-go capgo.app. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-88864/ (Markdown: https://insights.sbomify.com/CVE-2026-88864/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-88864
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-88864
- OSV: https://osv.dev/vulnerability/CVE-2026-88864

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-88864/
Summaries are generated and may contain mistakes; the official description above is the record.