CVE-2020-36281 in Leptonica
Summary
by MITRE • 03/12/2021
Leptonica before 1.80.0 allows a heap-based buffer over-read in pixFewColorsOctcubeQuantMixed in colorquant1.c.
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Analysis
by VulDB Data Team • 03/31/2021
The vulnerability identified as CVE-2020-36281 represents a critical heap-based buffer over-read flaw within the Leptonica library version 1.80.0 and earlier. This issue specifically affects the pixFewColorsOctcubeQuantMixed function located in the colorquant1.c source file, which is a core component responsible for color quantization operations in image processing workflows. The vulnerability arises from insufficient input validation and boundary checking when handling image data during the quantization process, creating a scenario where maliciously crafted input can cause the application to read beyond allocated memory boundaries.
The technical nature of this vulnerability stems from improper memory management during color quantization operations where the function fails to validate the number of colors or the dimensions of input images before performing octree-based color quantization. When processing images with specific characteristics or malformed data, the algorithm attempts to access memory locations that have not been properly allocated or are outside the intended buffer boundaries. This over-read condition can result in information disclosure, application instability, or potentially remote code execution depending on the context of use and how the library is integrated into target applications. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and demonstrates characteristics consistent with heap-based memory corruption issues commonly exploited in software exploitation frameworks.
The operational impact of this vulnerability extends across numerous applications that rely on Leptonica for image processing, including document analysis systems, OCR engines, medical imaging software, and various computer vision applications. Attackers could leverage this vulnerability by crafting specially formatted image files that trigger the buffer over-read condition during color quantization operations. The exploitation potential increases when the vulnerable library is used in web applications or document processing services that accept user-uploaded images, as this creates a direct attack surface for remote exploitation. Organizations using affected versions of Leptonica in production environments face significant risk of data breaches, service disruption, or system compromise if attackers successfully exploit this vulnerability in their specific implementation contexts.
Mitigation strategies for CVE-2020-36281 primarily focus on immediate version upgrades to Leptonica 1.80.0 or later, which contain the necessary patches to address the buffer over-read condition. System administrators should prioritize updating all affected applications and services that utilize the vulnerable library, particularly those handling untrusted image input. Additional defensive measures include implementing strict input validation and sanitization for all image processing workflows, deploying memory corruption detection tools such as address sanitizers or heap profilers, and establishing network segmentation to limit potential attack vectors. The vulnerability also underscores the importance of maintaining up-to-date third-party libraries and implementing comprehensive software supply chain security practices to prevent similar issues from arising in future releases. Organizations should consider implementing runtime monitoring and anomaly detection systems to identify potential exploitation attempts targeting this class of memory corruption vulnerabilities.