CVE-2018-9958 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.0.1.1049. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the handling of Text Annotations. When setting the point attribute, the process does not properly validate the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to execute code under the context of the current process. Was ZDI-CAN-5620.
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Analysis
by VulDB Data Team • 09/29/2025
CVE-2018-9958 represents a critical buffer overflow vulnerability in Foxit Reader version 9.0.1.1049 that stems from improper input validation within the text annotation processing component. This vulnerability falls under the CWE-125 weakness category, which specifically addresses out-of-bounds read conditions where an application attempts to access memory locations beyond the bounds of a buffer. The flaw manifests when the application processes maliciously crafted PDF files containing specially constructed text annotations that manipulate the point attribute parameter without adequate validation of object existence. This oversight creates a predictable exploitation vector that allows remote attackers to execute arbitrary code with the privileges of the current user process. The vulnerability requires user interaction to be successfully exploited, meaning that victims must either visit a malicious website hosting a crafted PDF or open a malicious file directly, making it particularly dangerous in phishing campaigns and targeted attacks.
The technical exploitation of this vulnerability leverages the principle of uninitialized memory access and improper object validation within the PDF rendering engine. When Foxit Reader encounters a text annotation with malformed point attributes, the application fails to verify whether the referenced object exists or has been properly initialized before attempting to perform operations on it. This lack of proper validation creates a path where attacker-controlled data can influence memory access patterns, potentially leading to stack corruption, heap manipulation, or direct code execution. The vulnerability's classification aligns with ATT&CK technique T1203 - Exploitation for Client Execution, as it enables attackers to execute malicious code through compromised PDF reader applications. The attack surface is particularly concerning given that Foxit Reader is widely used for document viewing across enterprise environments, making this vulnerability a prime target for advanced persistent threat actors seeking to establish persistent access.
The operational impact of CVE-2018-9958 extends beyond simple code execution, as successful exploitation can lead to complete system compromise and data exfiltration. Attackers can leverage this vulnerability to bypass traditional security controls, establish backdoors, or deploy additional malware payloads that persist across system reboots. The vulnerability's remote exploitation capability means that attackers can target users without requiring physical access to the target systems, making it particularly dangerous in corporate environments where PDF documents are frequently shared through email and collaboration platforms. Organizations utilizing Foxit Reader for document management, legal proceedings, or business communications face significant risk exposure, as the vulnerability can be exploited through legitimate business processes such as document sharing and collaboration. The ZDI-CAN-5620 reference indicates that this vulnerability was actively tracked by the Zero Day Initiative, highlighting its significance in the cybersecurity community and the need for immediate remediation.
Mitigation strategies for CVE-2018-9958 should prioritize immediate patching of Foxit Reader installations to version 9.0.2.1049 or later, which contains the necessary fixes for the text annotation validation flaw. Network administrators should implement strict PDF file filtering policies, particularly blocking PDF documents from untrusted sources and monitoring for suspicious file attachments in email systems. The principle of least privilege should be enforced by running Foxit Reader with minimal user permissions and avoiding execution with administrative privileges. Additional defensive measures include deploying sandboxing solutions for PDF processing, implementing web application firewalls to filter malicious PDF content, and conducting regular security assessments of document handling processes. Organizations should also consider implementing endpoint detection and response solutions that can identify suspicious behavior patterns associated with exploitation attempts, particularly those involving memory manipulation and code execution activities. The vulnerability serves as a reminder of the importance of regular software updates and proper input validation practices in preventing remote code execution attacks.