Description

Foxit PDF Editor/Reader’s U3D/GIF texture decoding path contained insufficient validation of image dimensions and related size information. Under certain conditions, this could lead to an incorrectly sized memory allocation and a subsequent out-of-bounds write during pixel processing, potentially resulting in remote code execution.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.8",
  "pubDate": "2026-09-23T08:17:10.753Z",
  "pubdate": "2026-09-23T08:17:10.753Z",
  "executiveSummary": "This vulnerability is an out-of-bounds (OOB) write flaw residing within the U3D and GIF texture decoding modules of Foxit PDF Editor and Reader. The vulnerability stems from improper validation of image dimension parameters and metadata during the parsing process, leading to heap-based memory corruption.\nSuccessful exploitation allows a remote, unauthenticated attacker to execute arbitrary code within the context of the current user. The attack vector requires the user to open a maliciously crafted PDF file containing specially formatted U3D or GIF objects. The risk is critical, as it bypasses standard application-level security controls through memory manipulation.\nImpact includes complete system compromise, unauthorized data access, and potential installation of persistent malware. Because the flaw occurs during the rendering of complex embedded media, it presents a significant threat to end-users who frequently interact with untrusted PDF documents.",
  "technicalDetails": "The vulnerability is localized within the image decoding sub-components responsible for processing U3D (Universal 3D) and GIF texture data. When the application parses these specific file formats, it performs memory allocations based on header information, such as width, height, and bit depth. The failure occurs due to insufficient bounds checking on these parameters before the allocation of the pixel buffer.\nSpecifically, when an attacker provides a crafted PDF containing an image with malicious dimensions, the application may calculate an insufficient buffer size, leading to an integer overflow or underflow during the allocation phase. Once the heap-allocated memory is initialized, the subsequent rendering logic attempts to populate the buffer using the attacker-controlled image data. Because the actual pixel data dimensions exceed the allocated buffer size, the application performs an out-of-bounds write operation, overwriting adjacent memory segments on the heap.\nThe exploitation flow follows these stages: First, the attacker embeds a malicious U3D or GIF object into a PDF document. Second, upon opening the document, the Foxit rendering engine triggers the vulnerable parsing logic. Third, the attacker leverages the OOB write to corrupt sensitive structures in memory, such as function pointers or object vtables. By carefully controlling the heap layout, the attacker can redirect the program execution flow to a controlled payload, such as a ROP chain or shellcode, thereby achieving remote code execution (RCE).\nThis vulnerability is particularly dangerous because it does not require prior authentication and can be triggered via standard social engineering tactics, such as emailing a malicious PDF to a targeted user. Post-exploitation, the attacker gains the same privileges as the user running the Foxit application. If the application is running with elevated privileges, the attacker could effectively gain full control over the host system. The lack of robust validation in the decoding path confirms that the application trusts input dimensions derived directly from the file structure without verifying them against physical memory limits or logical sanity constraints."
}