CVE-2026-66674

Simple CAPTCHA with Cloudflare Turnstile <= 1.42.1 - Captcha Bypass

2026-09-08 00:00

Strategic Overview

Status: Patched in 1.42.3
Affected Plugin: Simple CAPTCHA with Cloudflare Turnstile
Affected Version: <= 1.42.1
CVSS: 5.3Medium
Weakness type: CWE-804 · Guessable CAPTCHA
CVE: CVE-2026-66674

View all Simple CAPTCHA with Cloudflare Turnstile vulnerabilities

At a glance

CVE-2026-66674 is a medium-severity Guessable CAPTCHA vulnerability in the Simple CAPTCHA with Cloudflare Turnstile WordPress plugin, affecting versions <= 1.42.1. It carries a CVSS score of 5.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 1.42.3; sites on affected versions should update now. Disclosed September 2026, reported by Ananda Dhakal.

Vulnerability Overview

The Simple CAPTCHA with Cloudflare Turnstile plugin for WordPress is vulnerable to Captcha Bypass in all versions up to, and including, 1.42.1. This makes it possible for unauthenticated attackers to bypass captcha.

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.

CWE-804: Guessable CAPTCHA

The product uses a CAPTCHA challenge, but the challenge can be guessed or automatically recognized by a non-human actor.

Remediation

Update to version 1.42.3, or a newer patched version

How does WordSec protect against this?

Because it turns on account access, WordSec's login security is the relevant layer: role-based two-factor, captcha and brute-force limits raise the cost of getting the account this needs. None of that substitutes for the fix: Simple CAPTCHA with Cloudflare Turnstile 1.42.3 closes this, and updating the plugin is the step that ends it.

Login Security
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-66674 https://www.wordfence.com/threat-intel/vulnerabilities/id/3dcf2f22-4202-4902-9883-eb4479fe1028 https://nvd.nist.gov/vuln/detail/CVE-2026-66674

Related records

Other vulnerabilities in Simple CAPTCHA with Cloudflare Turnstile

CVSS Vector

5.3

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityNone
IntegrityLow
AvailabilityNone

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