CVE-2021-27847 in libvips
Summary
by MITRE • 07/15/2021
Division-By-Zero vulnerability in Libvips 8.10.5 in the function vips_eye_point, eye.c#L83, and function vips_mask_point, mask.c#L85.
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Analysis
by VulDB Data Team • 07/19/2021
The CVE-2021-27847 vulnerability represents a critical division-by-zero error within the Libvips image processing library version 8.10.5, specifically impacting two core functions: vips_eye_point in eye.c at line 83 and vips_mask_point in mask.c at line 85. This flaw exists within the mathematical operations used for image analysis and processing, where the software fails to validate input parameters before performing arithmetic calculations that could result in division by zero conditions. The vulnerability stems from inadequate input sanitization and error handling mechanisms within the image processing pipeline, particularly when dealing with specific coordinate values or image dimensions that could lead to invalid mathematical operations.
The technical implementation of this vulnerability occurs when the vips_eye_point and vips_mask_point functions process image coordinates or pixel values without proper validation of denominator values in their mathematical computations. When these functions encounter scenarios where a division operation would result in a zero denominator, the application crashes or becomes unresponsive, creating a denial of service condition. This type of vulnerability falls under CWE-369, which specifically addresses the division by zero weakness, and represents a classic example of improper input validation in mathematical processing functions. The flaw is particularly concerning because it can be triggered through crafted image files or malformed input data that the library processes during normal image manipulation operations.
Operationally, this vulnerability poses significant risks to systems that rely on Libvips for image processing workflows, including web applications, content management systems, and digital asset management platforms. An attacker could exploit this weakness by uploading malicious image files designed to trigger the division-by-zero condition, leading to service disruption and potential system instability. The impact extends beyond simple denial of service as the vulnerability could be leveraged in broader attack chains, particularly in environments where image processing libraries are used as part of automated workflows or API endpoints. This aligns with ATT&CK technique T1499.001, which covers network denial of service attacks, and demonstrates how seemingly benign image processing functionality can become a vector for system compromise.
The mitigation strategy for CVE-2021-27847 requires immediate patching of the Libvips library to version 8.10.6 or later, which contains the necessary fixes for the division-by-zero conditions in the affected functions. Organizations should also implement input validation measures to sanitize image file uploads and consider implementing rate limiting or file type restrictions for image processing workflows. Security teams should monitor for exploitation attempts through network traffic analysis and implement proper error handling in applications that utilize Libvips to prevent cascading failures. The vulnerability highlights the importance of robust input validation in mathematical processing functions and demonstrates how even well-established libraries can contain critical flaws that require ongoing security assessment and patch management processes.