CVE-2024-56527: 
PHP vulnerability analysis and mitigation

A cross-site scripting (XSS) vulnerability was discovered in TCPDF versions before 6.8.0. The vulnerability exists in the Error function which lacks proper sanitization through htmlspecialchars for error messages (NVD, CVE).

The vulnerability stems from the Error function's failure to properly sanitize error messages before rendering them. When an error occurs during PDF generation, the function displays the error message without adequate sanitization, potentially allowing for cross-site scripting attacks. The issue has been classified as CWE-79 (Improper Neutralization of Input During Web Page Generation) (NVD).

In scenarios where an attacker can input data that triggers an error, this vulnerability could lead to cross-site scripting attacks. For example, if an attacker can specify a malicious font name that causes an error, the unsanitized error message containing the malicious input would be displayed to users (Medium).

The vulnerability can be exploited in any function where an attacker can input data that could cause an error. A practical example involves attempting to set an invalid font name that contains malicious JavaScript code, which would then be displayed unsanitized in the error message (Medium).

The vulnerability has been fixed in TCPDF version 6.8.0 by implementing proper sanitization of error messages using the htmlspecialchars() function. Users are advised to upgrade to version 6.8.0 or later to address this security issue (GitHub).