CVE-2016-9535 in macOS
Summary
by MITRE
tif_predict.h and tif_predict.c in libtiff 4.0.6 have assertions that can lead to assertion failures in debug mode, or buffer overflows in release mode, when dealing with unusual tile size like YCbCr with subsampling. Reported as MSVR 35105, aka "Predictor heap-buffer-overflow."
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Analysis
by VulDB Data Team • 05/30/2026
The vulnerability identified as CVE-2016-9535 represents a critical security flaw within the libtiff library version 4.0.6, specifically affecting the tif_predict.h and tif_predict.c files that handle predictor functionality for TIFF image files. This issue manifests when processing images with unusual tile configurations, particularly those employing YCbCr color space with subsampling techniques. The flaw demonstrates a classic example of inadequate input validation and memory management that can lead to both denial of service conditions and potential exploitation vectors. The vulnerability was originally reported as Microsoft Security Vulnerability Research (MSVR) 35105, highlighting its significance in the broader security landscape.
The technical root cause of this vulnerability stems from insufficient boundary checking within the predictor prediction code that handles tile-based image processing. When libtiff encounters TIFF files with specific tile configurations involving YCbCr subsampling, the assertion mechanisms fail to properly validate memory boundaries during buffer operations. In debug compilation modes, this leads to assertion failures that terminate application execution, while in release builds, the same conditions can result in heap-based buffer overflows. The flaw specifically occurs during the prediction process where the library attempts to calculate and apply predictor values for compressed image data, particularly when dealing with subsampled chrominance components that require special handling.
The operational impact of CVE-2016-9535 extends beyond simple application crashes, presenting potential security risks in environments where libtiff is used for image processing. Systems utilizing this library for handling user-uploaded images, document processing, or image server applications become vulnerable to denial of service attacks that can render services unavailable. The buffer overflow condition in release mode creates opportunities for memory corruption that could potentially be exploited by malicious actors to execute arbitrary code, particularly in applications that do not implement proper input sanitization. This vulnerability affects any software that relies on libtiff for TIFF file processing, including web applications, image servers, and document management systems.
Mitigation strategies for this vulnerability require immediate attention from system administrators and software developers. The primary solution involves upgrading to libtiff version 4.0.7 or later, which contains the necessary patches to address the buffer overflow conditions and assertion failures. Organizations should implement comprehensive patch management processes to ensure all systems utilizing libtiff are updated promptly. Additional defensive measures include implementing input validation layers that can detect and reject malformed TIFF files before they reach the libtiff processing components. Security monitoring should be enhanced to detect unusual patterns in image processing requests that might indicate exploitation attempts. This vulnerability aligns with CWE-121, heap-based buffer overflow, and could potentially map to ATT&CK techniques involving execution through libraries and privilege escalation through memory corruption. The remediation process should also include code reviews to identify similar patterns in other image processing libraries and implementation of proper error handling mechanisms that prevent assertion failures from cascading into exploitable conditions.