CVE-2025-62707 is a vulnerability classified under CWE-834 (Excessive Iteration) affecting the py-pdf pypdf library, a widely used pure-Python PDF processing tool. Versions prior to 6.1.3 contain a flaw where an attacker can craft a specially designed PDF file that includes an inline image using the DCTDecode filter. When pypdf parses the content stream of such a page, it enters an infinite loop due to excessive iteration triggered by the crafted content. This infinite loop results in denial of service (DoS) by consuming CPU resources indefinitely, potentially causing application or system unresponsiveness. The vulnerability requires no authentication or user interaction, and can be exploited remotely by simply providing the malicious PDF to a vulnerable system. The CVSS 4.0 base score is 6.6 (medium severity), reflecting the network attack vector, no privileges required, no user interaction, and a high impact on availability. The vulnerability has been addressed and fixed in pypdf version 6.1.3. No public exploits or active exploitation have been reported to date. This vulnerability is particularly relevant for organizations that use pypdf for automated PDF processing, document management, or content extraction, especially when handling untrusted or external PDF files.

The primary impact of CVE-2025-62707 is denial of service through resource exhaustion caused by an infinite loop during PDF parsing. For European organizations, this can disrupt critical document processing workflows, automated reporting, or content extraction services that rely on pypdf. Industries such as finance, legal, government, and publishing, which frequently handle large volumes of PDFs, may experience service outages or degraded performance. The vulnerability does not directly compromise confidentiality or integrity but can indirectly affect business continuity and availability of services. Since exploitation requires no authentication or user interaction, any exposed system processing PDFs with vulnerable pypdf versions is at risk. The lack of known exploits reduces immediate risk, but the ease of exploitation and potential impact on availability warrant prompt remediation. Organizations using pypdf in web applications, cloud services, or internal tools should prioritize patching to avoid operational disruptions.

1. Upgrade all instances of pypdf to version 6.1.3 or later to ensure the vulnerability is patched. 2. Implement strict input validation and sanitization for all PDF files, especially those received from untrusted or external sources. 3. Employ sandboxing or resource limiting techniques when processing PDFs to prevent infinite loops from impacting critical systems. 4. Monitor application logs and system resource usage for signs of abnormal CPU consumption during PDF processing. 5. Where possible, isolate PDF processing services to minimize impact on other systems in case of exploitation. 6. Educate developers and system administrators about the vulnerability and ensure secure coding practices when integrating PDF libraries. 7. Regularly review and update third-party dependencies to incorporate security patches promptly.