CVE-2026-57240 in PDF Editor
Summary
by MITRE • 07/08/2026
When the application opens a PDF file and JavaScript deletes the PDF fields, the subsequent logic still uses the old field pointers, resulting in invalid pointer references and causing the application to crash.
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Analysis
by VulDB Data Team • 07/08/2026
This vulnerability represents a classic use-after-free condition that occurs when an application processes pdf documents containing javascript functionality. The flaw manifests when javascript code within a pdf document executes commands that delete form fields while the application continues to reference those deleted field pointers in subsequent operations. This type of memory safety issue falls under the broader category of improper neutralization of special elements used in os command injection and can be classified as cwe-416 use after free. The vulnerability specifically impacts pdf processing applications that fail to properly validate field existence before accessing field pointers, creating a scenario where freed memory locations are accessed leading to application instability.
The technical execution of this vulnerability involves multiple stages of pdf document parsing where javascript execution triggers field deletion operations followed by continued reference to those deleted objects. When the pdf parser encounters javascript code that modifies form fields, it may remove certain field entries from memory while simultaneously maintaining internal references to those locations. Subsequent application logic that attempts to access these now-invalid pointers causes segmentation faults or access violations that result in application crashes. This behavior aligns with attack technique t1059 007 scripting and demonstrates how malicious pdf documents can leverage javascript capabilities to exploit memory management flaws within pdf viewers.
The operational impact of this vulnerability extends beyond simple application instability to potentially enable more sophisticated attacks if exploited in conjunction with other memory corruption vulnerabilities. Applications that handle untrusted pdf content are particularly at risk, as attackers can craft malicious documents that trigger the use-after-free condition during normal document processing operations. This vulnerability affects a wide range of pdf processing software including web browsers with built-in pdf viewers, dedicated pdf readers, and document management systems that process pdf files programmatically. The crash behavior can be leveraged for denial of service attacks against targeted applications or systems that rely on pdf processing capabilities.
Mitigation strategies should focus on implementing proper pointer validation mechanisms within pdf processing applications to ensure that field references are checked before access operations occur. Developers must implement defensive programming practices that verify object existence and memory validity before accessing field pointers, particularly in javascript execution contexts where field modifications can occur dynamically. Memory safety improvements such as automatic null pointer checks, reference counting mechanisms, or secure memory management routines should be integrated into pdf processing libraries to prevent invalid pointer dereferences. Additionally, applications should implement proper error handling and graceful degradation when encountering corrupted or malicious pdf content rather than allowing crashes to occur during document processing operations.