Xerte Online Toolkits Path Traversal Vulnerability

Xerte Online Toolkits, a tool used to create online learning materials, is vulnerable to a path traversal vulnerability (CVE-2026-34414) in versions 3.15 and earlier. The vulnerability exists in the elFinder connector endpoint at /editor/elfinder/php/connector.php. The name parameter within rename commands is not properly sanitized, allowing attackers to use directory traversal sequences (e.g., ../) to manipulate file locations. This flaw can be exploited to overwrite application files, inject stored cross-site scripting (XSS), or, when combined with other vulnerabilities, achieve unauthenticated remote code execution (RCE). This poses a significant threat to organizations utilizing affected versions of Xerte Online Toolkits, potentially leading to data breaches, system compromise, and reputational damage.

Attack Chain

1. An attacker identifies a vulnerable Xerte Online Toolkits instance running version 3.15 or earlier.
2. The attacker crafts a malicious HTTP request to /editor/elfinder/php/connector.php targeting the rename command.
3. Within the request, the name parameter contains directory traversal sequences (e.g., ../../) and the desired destination path.
4. The server, due to insufficient input validation, processes the request without properly sanitizing the name parameter.
5. The attacker moves a file (e.g., an uploaded image or media file) from its original project media directory to a new location specified within the malicious name parameter. This could involve moving a file to the application root directory.
6. If the attacker moves a specifically crafted PHP file to the application root and the webserver is configured to execute PHP files in the root, the attacker can then access this file via a web request.
7. The attacker executes arbitrary code on the server.
8. The attacker gains complete control of the Xerte Online Toolkits instance and potentially the underlying server.

Impact

Successful exploitation of this vulnerability can lead to several critical consequences. Attackers can overwrite sensitive application files, leading to denial of service or system instability. The injection of malicious JavaScript code can result in stored cross-site scripting (XSS) attacks, compromising user accounts and data. The most severe outcome is unauthenticated remote code execution (RCE), enabling attackers to gain complete control over the affected server, potentially leading to data breaches, malware deployment, and further lateral movement within the network. The CVSS v3.1 base score for this vulnerability is 7.1, indicating a high level of risk.

Recommendation

• Upgrade Xerte Online Toolkits to a version greater than 3.15 to patch CVE-2026-34414.
• Deploy the Sigma rule Detect Suspicious Path Traversal in Xerte Connector to identify attempted exploitation of the path traversal vulnerability by monitoring requests to /editor/elfinder/php/connector.php with directory traversal sequences.
• Implement input validation and sanitization on the name parameter within the elFinder connector to prevent path traversal attacks.
• Review web server configurations to prevent the execution of PHP files from the web root directory.