CVE-2016-9297 in LibTIFF
Summary
by MITRE
The TIFFFetchNormalTag function in LibTiff 4.0.6 allows remote attackers to cause a denial of service (out-of-bounds read) via crafted TIFF_SETGET_C16ASCII or TIFF_SETGET_C32_ASCII tag values.
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Analysis
by VulDB Data Team • 05/13/2026
The vulnerability identified as CVE-2016-9297 represents a critical out-of-bounds read flaw within the LibTiff library version 4.0.6, specifically within the TIFFFetchNormalTag function. This issue arises from inadequate input validation when processing TIFF_SETGET_C16ASCII or TIFF_SETGET_C32_ASCII tag values, creating a scenario where remote attackers can manipulate the library's behavior through carefully crafted malicious TIFF files. The vulnerability stems from improper bounds checking during the parsing of character string data within TIFF metadata structures, allowing attackers to trigger memory access violations that ultimately result in denial of service conditions.
The technical implementation of this vulnerability demonstrates a classic buffer over-read condition where the TIFFFetchNormalTag function fails to properly validate the length of character data before attempting to access memory locations beyond the allocated buffer boundaries. When processing TIFF_SETGET_C16ASCII or TIFF_SETGET_C32_ASCII tags, the function assumes certain data structures and memory layouts without sufficient validation, leading to situations where memory addresses are accessed that fall outside the legitimate data boundaries. This flaw operates at the intersection of memory safety and data parsing, where the library's failure to implement proper bounds checking creates exploitable conditions that can be leveraged remotely.
From an operational impact perspective, this vulnerability poses significant risks to systems that process TIFF image files from untrusted sources, including web applications, document management systems, and image processing pipelines. The denial of service condition can be triggered by simply uploading or processing a malicious TIFF file, potentially causing application crashes, system instability, or complete service unavailability. Attackers can exploit this vulnerability without requiring authentication or special privileges, making it particularly dangerous in environments where automated image processing occurs. The impact extends beyond simple service disruption to potentially enable more sophisticated attacks if combined with other vulnerabilities in the processing pipeline.
The vulnerability aligns with CWE-125: Out-of-Bounds Read, which specifically addresses conditions where programs access memory locations beyond the bounds of allocated buffers. This classification emphasizes the fundamental nature of the flaw as a memory safety issue that occurs during data processing operations. From an ATT&CK framework perspective, this vulnerability maps to T1499.004: Network Denial of Service, where adversaries leverage software flaws to disrupt network services. The vulnerability also relates to T1595.001: Active Scanning, as attackers may systematically test systems for this specific flaw, and T1203: Exploitation for Client Execution, since the vulnerability can be triggered through client-side image processing operations.
Mitigation strategies for CVE-2016-9297 should prioritize immediate patching of affected LibTiff installations to version 4.0.7 or later, which contains the necessary fixes for the out-of-bounds read conditions. Organizations should implement input validation controls that sanitize TIFF file inputs before processing, including length verification for character string data and bounds checking for all tag values. Network segmentation and application whitelisting can provide additional defense-in-depth layers, preventing unauthorized systems from processing untrusted TIFF content. Regular vulnerability assessments and security testing should be conducted to identify similar memory safety issues within other image processing libraries and applications that may be susceptible to analogous flaws. System monitoring should be enhanced to detect unusual application behavior or crash patterns that may indicate exploitation attempts, while incident response procedures should include specific protocols for handling denial of service conditions related to image processing components.