CVE-2024-24246 identifies a heap buffer overflow vulnerability in qpdf version 11.9.0, a widely used open-source tool for PDF transformation and inspection. The flaw resides in the std::__shared_count() function implementation found in the C++ standard library header shared_ptr_base.h, which manages reference counting for shared pointers. When qpdf processes specially crafted PDF files, this vulnerability can be triggered, leading to heap corruption and ultimately causing the application to crash. The vulnerability is classified under CWE-122 (Heap-based Buffer Overflow). According to the CVSS 3.1 vector (5.5 medium severity), the attack requires local access (AV:L), low attack complexity (AC:L), no privileges (PR:N), and user interaction (UI:R). The impact is limited to availability (A:H), with no confidentiality or integrity loss. No known exploits have been reported in the wild, and no patches are currently available, indicating that mitigation relies on defensive measures and monitoring until a fix is released. This vulnerability primarily poses a denial-of-service risk, which could disrupt automated PDF processing pipelines or services relying on qpdf. Organizations using qpdf in environments where untrusted PDF files are processed should consider this a significant risk vector.

For European organizations, the primary impact of CVE-2024-24246 is denial of service due to application crashes when processing malicious PDF files. This can disrupt business operations that depend on qpdf for PDF manipulation, such as document management systems, automated workflows, or security scanning tools. While the vulnerability does not compromise data confidentiality or integrity, service interruptions could affect productivity and availability of critical document processing services. Industries such as finance, legal, government, and healthcare that rely heavily on PDF documents and automated processing may experience operational delays. Additionally, denial of service could be leveraged as part of a broader attack to cause disruption or distract from other malicious activities. Since exploitation requires local access and user interaction, the risk is somewhat mitigated in tightly controlled environments but remains relevant in scenarios where users handle untrusted PDFs or where qpdf is integrated into user-facing applications.

1. Restrict access to systems running qpdf 11.9.0 to trusted users only and limit exposure to untrusted PDF files. 2. Implement strict input validation and sandboxing for PDF files before processing with qpdf to prevent malicious files from triggering the vulnerability. 3. Monitor application logs and system behavior for crashes or abnormal terminations related to qpdf processes to detect potential exploitation attempts. 4. Employ endpoint protection solutions that can detect anomalous behavior or heap corruption indicative of exploitation. 5. Maintain an inventory of qpdf usage across the organization to identify vulnerable instances. 6. Prepare to apply patches or updates promptly once the qpdf maintainers release a fix for this vulnerability. 7. Educate users about the risks of opening untrusted PDF files and enforce policies to minimize user interaction with potentially malicious documents. 8. Consider alternative PDF processing tools with no known vulnerabilities if immediate patching is not feasible.