CVE-2020-35524 in LibTIFF
Summary
by MITRE • 03/10/2021
A heap-based buffer overflow flaw was found in libtiff in the handling of TIFF images in libtiff's TIFF2PDF tool. A specially crafted TIFF file can lead to arbitrary code execution. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.
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Analysis
by VulDB Data Team • 11/11/2025
The vulnerability identified as CVE-2020-35524 represents a critical heap-based buffer overflow within the libtiff library's TIFF2PDF conversion tool. This flaw exists in the manner in which the software processes specially crafted TIFF image files, creating a pathway for malicious actors to execute arbitrary code on affected systems. The vulnerability resides in the heap memory management of the TIFF2PDF utility, which fails to properly validate input data length when processing image metadata and pixel data structures. When a malicious TIFF file is processed through this tool, the insufficient bounds checking allows attackers to overwrite adjacent heap memory locations, potentially leading to code execution. The security implications extend beyond simple exploitation as this vulnerability affects the fundamental integrity of the system by compromising confidentiality, integrity, and availability through a single attack vector.
The technical nature of this vulnerability aligns with CWE-121, heap-based buffer overflow, and represents a classic memory corruption flaw that has been prevalent in image processing libraries for years. The flaw manifests specifically during the TIFF to PDF conversion process where the software does not adequately validate the size of data structures within the TIFF file format. Attackers can craft TIFF files containing oversized data fields or malformed metadata that cause the TIFF2PDF tool to allocate insufficient heap memory for processing. This insufficient memory allocation combined with unchecked data copying creates the conditions for buffer overflow, where adjacent memory regions become overwritten with attacker-controlled data. The vulnerability is particularly dangerous because it operates at the conversion tool level rather than the core library, making it exploitable through legitimate use of the software's functionality.
The operational impact of this vulnerability extends across multiple security domains and affects systems that process TIFF images through the libtiff library. Organizations relying on TIFF2PDF for document conversion, digital archiving, or image processing workflows face significant risk of compromise when using vulnerable versions of libtiff. The attack surface includes any system that accepts or processes TIFF files, particularly web applications, document management systems, and digital imaging platforms. This vulnerability can be exploited through various attack vectors including malicious file uploads, automated processing of external image sources, or even through compromised image repositories. The potential for remote code execution makes this a particularly attractive target for threat actors seeking persistent access to systems, as successful exploitation can lead to complete system compromise. The impact on system availability is substantial as successful exploitation can cause application crashes, system instability, or complete service denial.
Mitigation strategies for CVE-2020-35524 should prioritize immediate patching of affected libtiff versions, with particular attention to the TIFF2PDF tool implementation. Organizations must implement strict input validation measures for all TIFF file processing, including size limitations and format verification before any conversion occurs. The implementation of sandboxing techniques for image processing workflows can provide additional defense in depth, isolating the TIFF2PDF tool from critical system resources. Network segmentation and access controls should be enforced to limit exposure of systems running vulnerable versions of the library. Security monitoring should include detection of suspicious file processing patterns and unusual memory allocation behavior that may indicate exploitation attempts. The vulnerability also highlights the importance of maintaining up-to-date software libraries and implementing automated patch management processes to prevent similar issues from arising in the future. Organizations should consider implementing file type restrictions and content inspection for TIFF files, particularly in environments where untrusted input is processed. Compliance with security standards such as those outlined in the OWASP Top Ten and NIST cybersecurity guidelines should be maintained to ensure comprehensive protection against this class of vulnerability.