CVE-2026-90977

Clean Login <= 1.18 - Unauthenticated CAPTCHA Bypass

2026-09-16 00:00

Strategic Overview

Status: Patched in 1.19
Affected Plugin: Clean Login
Affected Version: <= 1.18
CVSS: 5.3Medium
Weakness type: CWE-804 · Guessable CAPTCHA
CVE: CVE-2026-90977

At a glance

CVE-2026-90977 is a medium-severity Guessable CAPTCHA vulnerability in the Clean Login WordPress plugin, affecting versions <= 1.18. 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 1.19; sites on affected versions should update now. Disclosed September 2026, reported by Arthur Morgan.

Vulnerability Overview

The Clean Login plugin for WordPress is vulnerable to CAPTCHA Bypass in all versions up to, and including, 1.18. This makes it possible for unauthenticated attackers to bypass captcha during registration.

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 1.19, 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: Clean Login 1.19 closes this, and updating the plugin is the step that ends it.

Login Security
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-90977 https://www.wordfence.com/threat-intel/vulnerabilities/id/20c92582-311e-45f9-8bbe-00c87d7e5656 https://nvd.nist.gov/vuln/detail/CVE-2026-90977

Related records

Other vulnerabilities in Clean Login

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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