CVE-2026-4407 in Xpdf
Summary
by MITRE • 03/19/2026
Out-of-bounds array write in Xpdf 4.06 and earlier, due to incorrect validation of the "N" field in ICCBased color spaces.
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Analysis
by VulDB Data Team • 03/23/2026
The vulnerability identified as CVE-2026-4407 represents a critical out-of-bounds array write flaw affecting Xpdf versions 4.06 and earlier, specifically within the handling of ICCBased color spaces. This issue arises from insufficient validation of the "N" field during the processing of color profile data, creating a potential avenue for arbitrary code execution or system compromise when malformed PDF documents are processed. The flaw exists within the color management subsystem of Xpdf, which is widely used for PDF rendering and manipulation across various platforms and applications.
The technical root cause stems from improper bounds checking when parsing the "N" field within ICCBased color spaces, which defines the number of color components in the color space. When an attacker crafts a malicious PDF document containing an ICCBased color space with an invalid or excessively large "N" value, the application fails to validate this parameter before attempting to write color data to an array. This results in memory corruption that can be exploited to overwrite adjacent memory locations, potentially leading to privilege escalation or remote code execution. The vulnerability aligns with CWE-129, which addresses insufficient validation of length parameters, and CWE-787, which covers out-of-bounds write conditions. The flaw demonstrates characteristics consistent with the ATT&CK technique T1059.007 for command and scripting interpreter usage, as exploitation may involve crafting malicious payloads that trigger the memory corruption during normal PDF processing operations.
The operational impact of this vulnerability extends beyond simple denial of service, as it can enable attackers to execute arbitrary code with the privileges of the affected application. When Xpdf processes malicious PDF documents containing crafted ICCBased color spaces, the out-of-bounds write can corrupt critical memory structures, potentially allowing attackers to inject and execute malicious code. This risk is particularly severe in environments where Xpdf is used as a backend component for web applications, document management systems, or security tools that process untrusted PDF content. The vulnerability affects not only direct Xpdf usage but also applications that rely on Xpdf for PDF rendering functionality, creating a wide attack surface across multiple software ecosystems. Organizations using vulnerable versions of Xpdf should consider this flaw as a critical security concern, as it can be exploited remotely through web-based PDF processing without requiring user interaction or specific privileges beyond the ability to deliver a malicious document.
Mitigation strategies for CVE-2026-4407 primarily focus on immediate version upgrades to Xpdf 4.07 or later, which contain the necessary patches to address the bounds checking vulnerability. System administrators should implement comprehensive patch management procedures to ensure all instances of Xpdf are updated promptly, particularly in environments where PDF processing occurs with untrusted content. Additional protective measures include implementing strict content filtering for PDF documents, deploying sandboxing mechanisms for PDF processing, and monitoring for anomalous memory access patterns that might indicate exploitation attempts. Network-based intrusion detection systems should be configured to detect potential exploitation attempts involving malformed ICCBased color spaces, while application-level security controls can enforce parameter validation for color space parameters. Organizations should also consider implementing least-privilege principles for Xpdf processes and establishing robust incident response procedures to address potential exploitation attempts. The vulnerability underscores the importance of regular security assessments and timely patch deployment, as it demonstrates how seemingly minor validation flaws in color management systems can lead to critical security consequences.