CVE-2025-50420 in Poppler
Summary
by MITRE • 08/04/2025
An issue in the pdfseparate utility of freedesktop poppler v25.04.0 allows attackers to cause an infinite recursion via supplying a crafted PDF file. This can lead to a Denial of Service (DoS).
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Analysis
by VulDB Data Team • 09/07/2025
The vulnerability identified as CVE-2025-50420 affects the pdfseparate utility within the freedesktop poppler v25.04.0 software suite, representing a critical denial of service weakness that stems from improper input validation and recursive processing mechanisms. This flaw specifically targets the pdfseparate component which is designed to extract individual pages from multipage pdf documents, making it a core functionality within the poppler toolkit that processes pdf files for various applications across unix-like systems. The vulnerability manifests when the utility encounters a specially crafted pdf file that contains recursive structures or malformed page references that trigger infinite recursion during the processing phase.
The technical implementation of this vulnerability resides in how the pdfseparate utility handles complex pdf structures and recursive page references within pdf documents. When processing a maliciously constructed pdf file, the utility fails to implement proper recursion depth limits or termination conditions, allowing an attacker to craft a pdf document containing circular references or nested structures that cause the processing loop to continue indefinitely. This recursive behavior occurs at the parsing level where the utility attempts to traverse page hierarchies and extract individual pages, with the malicious pdf file containing references that point back to previously processed pages or create circular dependencies that prevent normal termination. The flaw can be classified under CWE-674 which specifically addresses "Uncontrolled Recursion" and aligns with ATT&CK technique T1499.100 which covers "Endpoint Denial of Service" through resource exhaustion attacks.
The operational impact of this vulnerability extends beyond simple service disruption as it affects systems that rely on poppler for pdf processing, including document management systems, web applications, and automated workflows that utilize pdfseparate for page extraction. An attacker can exploit this weakness by simply providing a malicious pdf file to any system running poppler v25.04.0, causing the pdfseparate utility to consume excessive cpu cycles and memory resources until the system becomes unresponsive or crashes. This vulnerability is particularly dangerous in automated environments where pdf processing occurs without user intervention, as it can be leveraged to perform sustained denial of service attacks against critical infrastructure. The resource exhaustion occurs at the application level rather than at the system level, making it difficult to detect through traditional network monitoring and potentially allowing attackers to remain undetected while consuming system resources.
Mitigation strategies for this vulnerability should prioritize immediate patching of affected systems to upgrade to poppler versions that contain fixes for the recursive processing issue. System administrators should implement input validation measures that restrict pdf file processing to known good formats and consider deploying sandboxing mechanisms that limit resource consumption during pdf processing operations. Network segmentation and access controls should be implemented to prevent unauthorized users from submitting pdf files to systems that utilize pdfseparate functionality. Additionally, monitoring solutions should be configured to detect unusual cpu and memory usage patterns that may indicate exploitation attempts. Organizations should also consider implementing automated pdf validation checks that identify potentially malicious pdf structures before they reach the pdfseparate utility, and maintain regular security assessments of their pdf processing workflows to identify similar vulnerabilities that may exist in other components of the poppler suite. The fix typically involves implementing proper recursion depth checking and establishing maximum processing limits for pdf structures to prevent infinite loops during page extraction operations.