CVE-2022-39381 is a medium-severity vulnerability affecting the MuhammaraJS Node.js module, which provides C/C++ bindings for PDF manipulation in Node.js and Electron environments. MuhammaraJS is a successor or replacement for the hummusjs library. The vulnerability arises from an unchecked return value leading to a NULL pointer dereference (CWE-690) when processing maliciously crafted PDF files, specifically when appending one PDF to another. This flaw can cause the application to crash, resulting in a Denial of Service (DoS) condition. The issue affects all versions of hummusjs and MuhammaraJS versions prior to 2.6.0. The vulnerability has been patched in MuhammaraJS 2.6.0, but no fix exists for hummusjs. The root cause is the failure to verify that a pointer returned from an internal function is non-NULL before dereferencing it, which leads to application instability or crash when handling malformed PDFs. No known exploits have been reported in the wild, and the vulnerability requires the processing of maliciously crafted PDFs, which implies that the attacker must supply or influence the input files processed by the vulnerable software. The vulnerability primarily impacts applications that rely on these libraries for PDF manipulation, including those built on Node.js or Electron platforms, potentially affecting document processing workflows, PDF generation, or editing tools that incorporate MuhammaraJS or hummusjs.

For European organizations, the primary impact of this vulnerability is the potential for Denial of Service in applications that use MuhammaraJS or hummusjs for PDF processing. This can disrupt business operations, particularly in sectors heavily reliant on automated document workflows such as legal, finance, government, and publishing. The DoS could be exploited by an attacker supplying malicious PDFs, causing application crashes and service interruptions. While the vulnerability does not directly lead to data breaches or code execution, the loss of availability can degrade service quality and may indirectly impact confidentiality and integrity if fallback mechanisms are insecure or if the DoS leads to operational errors. Organizations processing untrusted PDFs from external sources or customers are at higher risk. Since the vulnerability requires crafted input files, the attack surface is limited to scenarios where untrusted PDFs are ingested. The lack of a patch for hummusjs means legacy systems or applications still using this library remain vulnerable, increasing risk exposure. The impact is thus moderate but significant in environments where PDF processing is critical and continuous uptime is required.

1. Upgrade MuhammaraJS to version 2.6.0 or later to apply the official patch that addresses the NULL pointer dereference issue. 2. For applications still using hummusjs, consider migrating to MuhammaraJS 2.6.0 or newer, as no patch exists for hummusjs. 3. Implement strict input validation and sanitization to reject or quarantine PDFs from untrusted or unknown sources before processing. 4. Employ sandboxing or process isolation for PDF processing tasks to contain potential crashes and prevent service-wide outages. 5. Monitor application logs for crashes or errors related to PDF processing to detect potential exploitation attempts. 6. Establish robust error handling around PDF manipulation functions to gracefully handle unexpected input without crashing. 7. Where feasible, use alternative, actively maintained PDF libraries with strong security track records. 8. Educate developers and system administrators about the risks of processing untrusted PDFs and enforce policies restricting such operations. 9. Conduct regular dependency audits to identify and update vulnerable libraries promptly. 10. For Electron-based applications, ensure that the PDF processing components run with the least privileges necessary to limit impact of crashes or exploitation.