CVE-2026-13447

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.

Vulnerability class: Broken Authentication

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-13447?
CVE-2026-13447 is a critical-severity vulnerability, classified under Improper Authentication. CVSS score: 9.8/10. Published 2026-09-05.
How severe is CVE-2026-13447?
Critical severity. CVSS v3 base score is 9.8 out of 10.