CVE-2026-13447: Auth Bypass (CVSS 9.8)

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.

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CVSS v3.1 Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0038

Probability of exploitation

0.32%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-287 Improper Authentication

References

Other References

https://plugins.trac.wordpress.org/browser/mstore-api/tags/4.18.4/controllers/flutter-user.php#L829 https://plugins.trac.wordpress.org/browser/mstore-api/tags/4.18.4/controllers/flutter-user.php#L940 https://plugins.trac.wordpress.org/browser/mstore-api/tags/4.18.4/controllers/helpers/firebase-phone-auth-helper.php#L5 https://plugins.trac.wordpress.org/browser/mstore-api/trunk/controllers/flutter-user.php#L829 https://plugins.trac.wordpress.org/browser/mstore-api/trunk/controllers/flutter-user.php#L940 https://plugins.trac.wordpress.org/browser/mstore-api/trunk/controllers/helpers/firebase-phone-auth-helper.php#L5 https://www.wordfence.com/threat-intel/vulnerabilities/id/4a1127af-74f6-4748-9aee-5a8c6c2766a4?source=cve

Frequently Asked Questions

What is CVE-2026-13447? +

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. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-13447? +

CVE-2026-13447 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0038, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-13447? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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