# CVE-2026-88861: Capgo AAL1 Session MFA Bypass via Direct RBAC Authorization

> Attackers with a password can bypass MFA to gain admin privileges and modify production OTA configurations in Capgo.

- **Severity:** High 8.7 (`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`)
- **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-3rq3-733w-v2c4

## What is CVE-2026-88861?

CVE-2026-88861 is a high-severity authentication bypass 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 (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.

Weakness: CWE-288 (Authentication Bypass Using an Alternate Path or Channel)

## Which versions are affected by CVE-2026-88861?


## How do I fix CVE-2026-88861?

No fix has been published for CVE-2026-88861 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-88861 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-88861 exists.

Public exploit code:

- SecDim Challenge Builder repro inspired by CVE-2026-88861: AAL1 MFA bypass at privileged credential boundary (github_poc): https://github.com/franklincg/secdim-assurance-drift-challenge

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-88861 and fix it if it is affected.

What it is: CVE-2026-88861 is a high-severity authentication bypass 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-2026-88861 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-2026-88861/ (Markdown: https://insights.sbomify.com/CVE-2026-88861/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-88861
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-88861
- OSV: https://osv.dev/vulnerability/CVE-2026-88861

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-88861/
Summaries are generated and may contain mistakes; the official description above is the record.