# CVE-2026-13447: MStore API <= 4.20.0 - Unauthenticated Authentication Bypass via 'id_token' Parameter JWT Forgery

> Unauthenticated attackers can bypass authentication by forging JWTs due to missing signature verification, allowing account takeover or creation.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 5 Sep 2026
- **Updated:** 7 Sep 2026
- **Also known as:** GHSA-6wfp-pwm3-667v

## What is CVE-2026-13447?

CVE-2026-13447 is a critical authentication bypass vulnerability in inspireui MStore API – Create Native Android & iOS Apps On The Cloud, published on 5 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Mstore Api plugin for WordPress is vulnerable to Authentication Bypass via JWT Forgery in versions up to, and including, 4.20.0 This is due to missing cryptographic signature verification in the FirebasePhoneAuthHelper::verify_id_token() function, which decodes and validates Firebase ID token claims (alg, kid, aud, iss) but never calls openssl_verify() or any equivalent to validate the JWT signature against Google's actual public key certificates. This makes it possible for unauthenticated attackers to forge a Firebase Phone Auth JWT signed with a self-generated RSA key pair and impersonate any phone number, resulting in unauthorized access to existing WordPress accounts or creation of new arbitrary accounts.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-13447?


## How do I fix CVE-2026-13447?

No fix has been published for CVE-2026-13447 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-13447 being exploited?

There is no known exploitation of CVE-2026-13447 in the wild and no public exploit code.

Public exploit code:

- CVE-2026-13447 - WordPress - inspireui - Critical 9.8 - Unauthenticated POST /wp-json/api/flutter_user/firebase_sms_v2 - Authentication Bypass (github_poc): https://github.com/abraxas/CVE-2026-13447

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-13447 and fix it if it is affected.

What it is: CVE-2026-13447 is a critical authentication bypass vulnerability in inspireui MStore API – Create Native Android & iOS Apps On The Cloud, published on 5 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-13447 in the wild and no public exploit code.

Affected product: inspireui MStore API – Create Native Android & iOS Apps On The Cloud. 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-2026-13447/ (Markdown: https://insights.sbomify.com/CVE-2026-13447/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-13447
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-13447
- OSV: https://osv.dev/vulnerability/CVE-2026-13447

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-13447/
Summaries are generated and may contain mistakes; the official description above is the record.