Platform
php
Component
simple-chatbox
Fixed in
1.0.1
CVE-2026-6159 is a cross-site scripting (XSS) vulnerability affecting Simple ChatBox versions 1.0.0 through 1.0. This vulnerability allows attackers to inject malicious scripts into the application, potentially compromising user sessions and data. The vulnerability resides in the /chatbox/insert.php endpoint, specifically within the handling of the 'msg' parameter. A patch is anticipated, and interim mitigation strategies are available.
Successful exploitation of CVE-2026-6159 allows an attacker to execute arbitrary JavaScript code within the context of a victim's browser session. This can lead to various malicious outcomes, including session hijacking, credential theft, and defacement of the Simple ChatBox interface. An attacker could leverage this vulnerability to steal sensitive information, redirect users to malicious websites, or even gain control of the affected server if the application has elevated privileges. The impact is amplified if the Simple ChatBox application is integrated with other systems or processes, potentially leading to lateral movement within the network.
CVE-2026-6159 has been publicly disclosed, increasing the likelihood of exploitation. No KEV listing or EPSS score is currently available. Public proof-of-concept (PoC) code is likely to emerge given the vulnerability's simplicity and public disclosure. The vulnerability was published on 2026-04-13.
Exploit Status
EPSS
0.03% (10% percentile)
CISA SSVC
CVSS Vector
The primary mitigation for CVE-2026-6159 is to upgrade to a patched version of Simple ChatBox as soon as it becomes available. Until a patch is released, implement a Web Application Firewall (WAF) rule to filter or sanitize user input in the 'msg' parameter of the /chatbox/insert.php endpoint. Specifically, look for and block suspicious characters or patterns commonly used in XSS attacks. Input validation on the server-side is also crucial, ensuring that the 'msg' parameter is properly sanitized before being displayed to users. Regularly review and update WAF rules to adapt to evolving attack techniques.
Update the Simple ChatBox plugin to the latest available version to mitigate the XSS vulnerability. Verify the official plugin source for update instructions and security patches. Implement input validation and escaping measures to prevent future XSS attacks.
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CVE-2026-6159 is a cross-site scripting (XSS) vulnerability in Simple ChatBox versions 1.0.0–1.0, allowing attackers to inject malicious scripts via the 'msg' parameter in /chatbox/insert.php.
You are affected if you are using Simple ChatBox versions 1.0.0–1.0 and have not applied a patch or implemented mitigating controls such as a WAF.
Upgrade to a patched version of Simple ChatBox as soon as it becomes available. Until then, implement a WAF rule to sanitize user input in the 'msg' parameter.
CVE-2026-6159 has been publicly disclosed, increasing the likelihood of exploitation. Active exploitation is possible.
Refer to the Simple ChatBox project's official website or repository for updates and advisories regarding CVE-2026-6159.
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