CVE-2026-18356

Limit Login Attempts Security – Login Security, 2FA, Firewall, Brute Force Prevention < 3.3.5 - Unauthenticated Username Denylist Bypass

2026-08-17 00:00

Strategic Overview

Status: Patched in 3.3.5
Affected Plugin: Limit Login Attempts Security – Login Security, 2FA, Firewall, Brute Force Prevention
Affected Version: < 3.3.5
CVSS: 5.3Medium
Weakness type: CWE-693 · Protection Mechanism Failure
CVE: CVE-2026-18356

View all Limit Login Attempts Security – Login Security, 2FA, Firewall, Brute Force Prevention vulnerabilities

At a glance

CVE-2026-18356 is a medium-severity Protection Mechanism Failure vulnerability in the Limit Login Attempts Security WordPress plugin, affecting versions < 3.3.5. 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 3.3.5; sites on affected versions should update now. Disclosed August 2026, reported by Artus KG.

Vulnerability Overview

The Limit Login Attempts Security – Login Security, 2FA, Firewall, Brute Force Prevention plugin for WordPress is vulnerable to protection mechanism bypass in all versions up to 3.3.5 (exclusive). This makes it possible for unauthenticated attackers to use usernames that have been added to a denylist.

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-693: Protection Mechanism Failure

The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product.

Remediation

Update to version 3.3.5, 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: Limit Login Attempts Security 3.3.5 closes this, and updating the plugin is the step that ends it.

Login Security
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-18356 https://www.wordfence.com/threat-intel/vulnerabilities/id/1a5f48ac-a992-4496-b86b-f2e4554d4bd7 https://nvd.nist.gov/vuln/detail/CVE-2026-18356

Related records

Other vulnerabilities in Limit Login Attempts Security – Login Security, 2FA, Firewall, Brute Force Prevention

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

This record contains material that is subject to copyright

CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE®). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.

https://www.cve.org/Legal/TermsOfUse

Defiant hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute this software vulnerability information. Any copy of the software vulnerability information you make for such purposes is authorized provided that you include a hyperlink to this vulnerability record and reproduce Defiant's copyright designation and this license in any such copy.

https://www.wordfence.com/wordfence-intelligence-terms-and-conditions/