CVE-2025-3154 in Xpdf
Summary
by MITRE • 04/03/2025
Out-of-bounds array write in Xpdf 4.05 and earlier, triggered by an invalid VerticesPerRow value in a PDF shading dictionary.
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Analysis
by VulDB Data Team • 11/12/2025
The vulnerability identified as CVE-2025-3154 represents a critical out-of-bounds array write flaw within the Xpdf library version 4.05 and earlier implementations. This vulnerability manifests when processing PDF documents containing malformed shading dictionaries with invalid VerticesPerRow values, creating a scenario where the application fails to properly validate input data before attempting memory operations. The issue stems from insufficient bounds checking mechanisms within the PDF rendering engine's handling of shading objects, which are used to define gradient fills and complex color transitions in PDF documents. When the VerticesPerRow parameter contains an invalid value that exceeds expected memory allocation boundaries, the application attempts to write data beyond the allocated array memory region, potentially leading to memory corruption and arbitrary code execution.
The technical exploitation of this vulnerability involves crafting a malicious PDF document with a specifically crafted shading dictionary where the VerticesPerRow value is set to an excessive or negative integer. This causes the Xpdf library to allocate insufficient memory for the vertex array structure, followed by an out-of-bounds write operation when the rendering process attempts to populate the array with vertex data. The flaw aligns with CWE-787, which describes out-of-bounds write vulnerabilities, and demonstrates characteristics consistent with memory corruption vulnerabilities that can be leveraged for privilege escalation or remote code execution. The vulnerability operates at the intersection of PDF parsing and graphics rendering, where the library's failure to validate mathematical parameters in shading dictionaries creates a pathway for attackers to manipulate memory layout and potentially execute malicious code within the context of the application processing the PDF.
The operational impact of CVE-2025-3154 extends across numerous systems and applications that rely on Xpdf for PDF rendering functionality, including web browsers, document viewers, and enterprise content management systems. This vulnerability poses significant risks to organizations processing untrusted PDF content, as attackers can exploit it through simple PDF document delivery without requiring user interaction beyond opening the document. The attack surface is particularly concerning given that PDF documents are frequently encountered in email attachments, web downloads, and document sharing environments where security controls may be insufficient. The vulnerability can be classified under ATT&CK technique T1203, which covers exploitation for execution, as it allows for arbitrary code execution through the manipulation of PDF rendering parameters. Additionally, the flaw demonstrates characteristics of T1068, involving local privilege escalation, when the vulnerable application runs with elevated privileges or when the memory corruption leads to privilege escalation opportunities.
Mitigation strategies for CVE-2025-3154 require immediate implementation of software updates to Xpdf version 4.06 or later, which contain fixes for the bounds checking vulnerability. Organizations should also implement defensive measures such as PDF sandboxing, content filtering, and restricted PDF processing environments to reduce the attack surface. Network-level filtering can be employed to block PDF documents from untrusted sources, while application-level controls should enforce strict input validation and memory protection mechanisms. Regular security assessments of PDF processing pipelines and monitoring for anomalous PDF rendering behavior can help detect exploitation attempts. The vulnerability underscores the importance of robust input validation and memory safety practices in document processing libraries, particularly those handling complex graphics and rendering operations that manipulate mathematical parameters within structured data formats.