CVE-2026-3655

OTP Login With Phone Number, OTP Verification <= 1.8.60 - Unauthenticated Authentication Bypass via Firebase OTP Verification

2026-05-28 17:56
lucky_buddy

Strategic Overview

Status
Patched in 1.8.61
Affected Version
1.8.50 – 1.8.60
CVSS
9.8Critical
Weakness type
CWE-287 · Improper Authentication
CVE
CVE-2026-3655
View all OTP Login With Phone Number, OTP Verification vulnerabilities

At a glance

CVE-2026-3655 is a critical-severity Improper Authentication vulnerability in the OTP Login With Phone Number, OTP Verification WordPress plugin, affecting versions 1.8.50 – 1.8.60. It carries a CVSS score of 9.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 1.8.61; sites on affected versions should update now. Disclosed May 2026, reported by lucky_buddy.

Vulnerability Overview

The OTP Login With Phone Number, OTP Verification plugin for WordPress is vulnerable to authentication bypass in versions 1.8.50 through 1.8.60. This is due to the Firebase verification flow in the `lwp_ajax_register` AJAX handler not binding the Firebase session to the phone number supplied in the request. The `idehweb_lwp_activate_through_firebase()` function validates that a Firebase OTP session is legitimate, but the `phoneNumber` returned by Firebase is never compared against the victim's stored phone number. This makes it possible for unauthenticated attackers to authenticate as any user who has a phone number stored in user meta, including administrators, by verifying their own Firebase session and supplying the victim's phone number in the same request.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

CWE-287: Improper Authentication

OTP Login With Phone Number, OTP Verification 1.8.50 – 1.8.60 carries this weakness at idehweb_lwp_activate_through_firebase(), and reaching it takes no account at all. Improper authentication means the mechanism that proves who a caller is can be satisfied without the secret it was supposed to require.

An attacker authenticates as another user — administrators included — without ever knowing a password, so password policies and login rate limits never come into play. For OTP Login With Phone Number, OTP Verification the fix is 1.8.61: builds 1.8.50 – 1.8.60 are affected, anything from 1.8.61 onward is not.

Remediation

Update to version 1.8.61, or a newer patched version

How does WordSec protect against this?

This one needs no account at all, which puts it outside what login hardening can reach; WordSec's login security narrows the account-level paths around it, and the firewall is what inspects the request itself. None of that substitutes for the fix: OTP Login With Phone Number, OTP Verification 1.8.61 closes this, and updating the plugin is the step that ends it.

  • Login Security
  • Alerts

External References

Related records

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