Spam protection, Honeypot, Anti-Spam by CleanTalk <= 6.71 - Authorization Bypass via Reverse DNS (PTR record) Spoofing to Unauthenticated Arbitrary Plugin Installation

2026-02-14 14:21

Nguyen Ngoc Duc (duc193)

Strategic Overview

Status

Patched in 6.72

Affected PluginCleanTalk Anti-Spam. Spam Firewall & Bot protection

Affected Version<= 6.71

CVSS9.8Critical

CVECVE-2026-1490

View all CleanTalk Anti-Spam. Spam Firewall & Bot protection vulnerabilities

Vulnerability Overview

The Spam protection, Anti-Spam, FireWall by CleanTalk plugin for WordPress is vulnerable to unauthorized Arbitrary Plugin Installation due to an authorization bypass via reverse DNS (PTR record) spoofing on the 'checkWithoutToken' function in all versions up to, and including, 6.71. This makes it possible for unauthenticated attackers to install and activate arbitrary plugins which can be leveraged to achieve remote code execution if another vulnerable plugin is installed and activated. Note: This is only exploitable on sites with an invalid API key.

Technical Analysis

REMEDIATION: Update to version 6.72, or a newer patched version --- IDENTIFIER: CWE-350 (Reliance on Reverse DNS Resolution for a Security-Critical Action) The product performs reverse DNS resolution on an IP address to obtain the hostname and make a security decision, but it does not properly ensure that the IP address is truly associated with the hostname.

External References

https://www.cve.org/CVERecord?id=CVE-2026-1490 https://www.wordfence.com/threat-intel/vulnerabilities/id/cb603be6-4a12-49e1-b8cc-b2062eb97f16

CVSS Vector

9.8

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

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