CVE-2026-97347 in Post Views Stats Counter Plugin
Summary
by MITRE • 09/30/2026
The Post Views Stats Counter plugin for WordPress is vulnerable to Stored Cross-Site Scripting via User-Agent Header in all versions up to, and including, 1.1.7 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The plugin's only input filter is a substring blacklist for known bot signatures (e.g. 'bot', 'spider', 'crawler'), which can be trivially bypassed by crafting a User-Agent payload that omits those strings.
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Analysis
by VulDB Data Team • 09/30/2026
The Post Views Stats Counter plugin, widely utilized in WordPress environments to track and display page view statistics, contains a critical security flaw affecting all versions up through 1.1.7. This vulnerability manifests as a Stored Cross-Site Scripting (XSS) issue rooted in the handling of the HTTP User-Agent header. The core technical deficiency lies in insufficient input sanitization combined with inadequate output escaping when processing data derived from this specific request header. Unlike many other vectors that require user interaction or authentication, this flaw allows unauthenticated attackers to inject malicious scripts directly into the database by manipulating their browser's identity string during a page visit.
The operational mechanism of this exploit relies on the plugin's attempt to log visitor information for statistical purposes. When a user accesses a WordPress site running the vulnerable plugin, the server captures the User-Agent header sent by the client and stores it in the backend database without proper validation or encoding. The existing security control implemented within the plugin is rudimentary at best; it employs only a substring blacklist designed to filter out known bot signatures such as 'bot', 'spider', and 'crawler'. This approach fails to address the fundamental requirement of treating all input as untrusted, particularly when that input will be rendered in an HTML context. Consequently, any payload inserted into the User-Agent header is persisted on the server side rather than being blocked or neutralized at the point of entry.
The impact of this vulnerability extends beyond simple data persistence because the stored malicious content is subsequently retrieved and displayed to other users visiting the site. When a legitimate user loads a page where an attacker has previously injected their payload, the browser interprets the embedded script as part of the webpage's code. This execution occurs within the security context of the victim’s session with the WordPress site. As a result, attackers can perform actions such as stealing administrative cookies, hijacking sessions, defacing websites, or redirecting users to malicious external sites. The persistence of this data means that every subsequent visitor becomes a potential target for exploitation without needing any further interaction from the attacker after the initial injection.
This vulnerability aligns with Common Weakness Enumeration (CWE) identifiers such as CWE-79, which describes Improper Neutralization of Input During Web Page Generation commonly known as Cross-site Scripting, and specifically relates to stored variants where malicious scripts are permanently saved on target servers. From a tactical perspective, this attack vector corresponds to the ATT&CK technique T1059, Command and Scripting Interpreter, particularly when used for client-side script execution like JavaScript. The lack of robust input validation represents a classic failure in secure coding practices, highlighting the danger of relying solely on blacklists rather than implementing allow-lists or strict encoding strategies.
Mitigation requires immediate action to prevent further exploitation and remediate existing risks. Administrators should update the Post Views Stats Counter plugin to version 1.1.8 or later, where developers have addressed these sanitization issues by properly escaping output data before it is rendered in HTML contexts. Until an official patch is applied, site administrators can implement a Web Application Firewall (WAF) rule that inspects incoming User-Agent headers for common script injection patterns and blocks requests containing suspicious characters such as angle brackets or quotation marks. Additionally, enabling Content Security Policy headers on the web server can help mitigate the impact of any successfully injected scripts by restricting the sources from which executable content is allowed to load, thereby reducing the effectiveness of client-side attacks even if they occur.