CVE-2024-38356 in TinyMCE
Summary
by MITRE • 06/19/2024
TinyMCE is an open source rich text editor. A cross-site scripting (XSS) vulnerability was discovered in TinyMCE’s content extraction code. When using the `noneditable_regexp` option, specially crafted HTML attributes containing malicious code were able to be executed when content was extracted from the editor. This vulnerability has been patched in TinyMCE 7.2.0, TinyMCE 6.8.4 and TinyMCE 5.11.0 LTS by ensuring that, when using the `noneditable_regexp` option, any content within an attribute is properly verified to match the configured regular expression before being added. Users are advised to upgrade. There are no known workarounds for this vulnerability.
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Analysis
by VulDB Data Team • 04/30/2026
The vulnerability identified as CVE-2024-38356 represents a critical cross-site scripting flaw within the TinyMCE rich text editor ecosystem, specifically targeting the content extraction functionality when utilizing the noneditable_regexp configuration option. This vulnerability exists in the core processing logic that handles HTML attribute parsing and validation during content extraction operations, creating a pathway for malicious code execution through seemingly benign HTML attributes. The flaw stems from insufficient input validation mechanisms that fail to properly sanitize attribute values before they are processed and rendered back to users, making it particularly dangerous in web applications that rely on TinyMCE for content management and user-generated content processing.
Technical exploitation of this vulnerability occurs when attackers craft HTML attributes containing malicious payloads that bypass the regular expression validation intended to mark certain content as non-editable. The vulnerability manifests in the content extraction code path where TinyMCE processes HTML attributes without proper sanitization, allowing the malicious code to execute in the context of the victim's browser session. This behavior aligns with CWE-79 Cross-site Scripting vulnerability classification, specifically targeting the improper neutralization of input during web page generation. The flaw demonstrates a classic security oversight in attribute validation where the system assumes that content matching a regular expression pattern is safe, without considering that attribute values themselves might contain executable code that could be interpreted by browsers during rendering.
The operational impact of CVE-2024-38356 extends beyond simple script execution, potentially enabling attackers to perform session hijacking, data theft, or further exploitation within the targeted application environment. When content is extracted from the editor and subsequently rendered in web pages, malicious scripts embedded within HTML attributes can execute in the context of authenticated users, leading to privilege escalation or unauthorized access to sensitive information. This vulnerability affects all versions of TinyMCE prior to 5.11.0 LTS, 6.8.4, and 7.2.0, representing a significant attack surface for web applications that utilize rich text editing capabilities. The vulnerability's presence in widely deployed content management systems and web applications makes it particularly concerning from an enterprise security perspective, as it could be leveraged to compromise user sessions and gain unauthorized access to sensitive data within web applications that rely on TinyMCE for content editing.
The patch implemented by TinyMCE developers addresses this vulnerability by introducing proper validation mechanisms that ensure any content within HTML attributes is rigorously verified against the configured regular expression before being added to the content stream. This remediation follows the principle of input validation and output encoding as recommended in the OWASP Top Ten security framework, specifically addressing the XSS prevention techniques outlined in the ATT&CK framework under the T1059.001 technique for command and scripting interpreter. The fix requires that attribute values be strictly validated against the defined patterns rather than simply matching the overall element structure, preventing malicious code from being embedded within attribute values. Organizations should prioritize immediate upgrading to patched versions to eliminate this attack vector, as no effective workarounds exist for this vulnerability. The remediation approach demonstrates proper security engineering practices that align with the principle of least privilege and defense in depth, ensuring that content processing operations maintain strict validation boundaries to prevent unauthorized code execution.