CVE-2025-67843 is a Server-Side Template Injection (SSTI) vulnerability identified in the MDX Rendering Engine component of the Mintlify Platform, a tool used for rendering MDX files that combine Markdown and JSX. This vulnerability arises from improper neutralization of special elements within the template engine (classified under CWE-1336), allowing attackers to inject malicious inline JSX expressions. When an attacker submits a crafted MDX file containing these expressions, the server-side rendering engine executes arbitrary code, potentially leading to full system compromise. The vulnerability affects versions of Mintlify Platform prior to the 2025-11-15 update. The CVSS 3.1 base score is 8.3, indicating high severity, with the vector showing network attack vector (AV:N), low attack complexity (AC:L), requiring privileges (PR:L), no user interaction (UI:N), unchanged scope (S:U), and high impact on confidentiality and integrity (C:H/I:H) with low impact on availability (A:L). Although no public exploits are known, the vulnerability's nature allows remote attackers with limited privileges to execute code without user interaction, making it a significant threat. The MDX rendering process is critical in environments where dynamic content is generated from user-supplied or third-party MDX files, common in documentation platforms and developer tools. Exploitation could lead to data theft, unauthorized access, or disruption of services. The lack of available patches at the time of publication necessitates immediate attention to mitigation strategies.

For European organizations, the impact of CVE-2025-67843 can be substantial, particularly for those using the Mintlify Platform for documentation, content management, or developer collaboration. Successful exploitation could lead to unauthorized code execution on servers, resulting in data breaches, intellectual property theft, or service disruption. Confidentiality and integrity of sensitive information are at high risk, potentially affecting compliance with GDPR and other data protection regulations. The ability to execute arbitrary code remotely without user interaction increases the likelihood of automated attacks or worm-like propagation within corporate networks. Organizations in sectors such as finance, technology, and government, which rely heavily on secure documentation and developer tools, may face operational and reputational damage. Additionally, the vulnerability could be leveraged as a foothold for lateral movement or further exploitation within enterprise environments.

To mitigate CVE-2025-67843, organizations should: 1) Monitor Mintlify’s official channels closely for patches and apply updates immediately once released. 2) Implement strict input validation and sanitization on all MDX files uploaded or processed, specifically filtering or disallowing inline JSX expressions. 3) Restrict access to the MDX rendering functionality to trusted users and environments, employing role-based access controls to limit privileges. 4) Employ runtime application self-protection (RASP) or web application firewalls (WAFs) configured to detect and block suspicious template injection patterns. 5) Conduct regular security audits and code reviews focusing on template rendering components. 6) Isolate the rendering environment using containerization or sandboxing to limit the impact of potential exploitation. 7) Educate developers and content contributors about the risks of injecting untrusted code into MDX files. 8) Monitor logs and network traffic for unusual activity related to MDX processing to detect early signs of exploitation attempts.