CVE-2025-57803 in ImageMagick
Summary
by MITRE • 08/26/2025
ImageMagick is free and open-source software used for editing and manipulating digital images. Prior to versions 6.9.13-28 and 7.1.2-2 for ImageMagick's 32-bit build, a 32-bit integer overflow in the BMP encoder’s scanline-stride computation collapses bytes_per_line (stride) to a tiny value while the per-row writer still emits 3 × width bytes for 24-bpp images. The row base pointer advances using the (overflowed) stride, so the first row immediately writes past its slot and into adjacent heap memory with attacker-controlled bytes. This is a classic, powerful primitive for heap corruption in common auto-convert pipelines. This issue has been patched in versions 6.9.13-28 and 7.1.2-2.
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Analysis
by VulDB Data Team • 11/22/2025
The vulnerability identified as CVE-2025-57803 represents a critical integer overflow flaw within ImageMagick's BMP encoder implementation specifically affecting 32-bit builds. This issue stems from improper handling of scanline stride computation during image processing operations, creating a condition where the bytes_per_line parameter becomes severely truncated due to overflow. The vulnerability manifests when processing 24-bit per pixel images where the encoder computes a stride value that cannot accommodate the actual data requirements. The flaw occurs in the 32-bit build environment where integer overflow conditions are more readily exploitable due to the reduced bit width of the computational variables involved.
The technical exploitation of this vulnerability begins with the BMP encoder's incorrect calculation of row stride values during image processing. When the encoder processes 24-bit per pixel images, it should compute the stride as 3 times the image width to accommodate the three bytes per pixel. However, due to the integer overflow, this calculation collapses to a minimal value that cannot properly contain the actual data being written. The per-row writer continues to emit the full 3 × width bytes of data for each row, but the memory pointer advances based on the overflowed tiny stride value. This fundamental mismatch causes the first row of data to overwrite adjacent heap memory locations with attacker-controlled values, creating a heap corruption primitive that can be leveraged for arbitrary code execution.
The operational impact of this vulnerability extends beyond simple image processing contexts and represents a significant threat to systems that automatically process untrusted image files. The vulnerability is particularly dangerous in auto-convert pipelines where ImageMagick is used to automatically process and convert various image formats without manual intervention. Attackers can craft malicious BMP files that trigger this overflow condition, potentially leading to remote code execution when the vulnerable software processes these files. The heap corruption primitive created by this vulnerability provides attackers with the ability to manipulate memory layout and potentially execute malicious code with the privileges of the affected process, making it a severe security concern for web applications, content management systems, and any automated image processing infrastructure.
This vulnerability aligns with CWE-190, Integer Overflow or Wraparound, and represents a classic example of how improper integer handling can lead to memory corruption. The exploitation pattern follows ATT&CK technique T1203, Exploitation for Client Execution, as it enables remote code execution through crafted image files. The vulnerability's classification as a heap corruption primitive makes it particularly dangerous as it can be combined with other exploitation techniques to achieve more sophisticated attacks. The patch implemented in versions 6.9.13-28 and 7.1.2-2 addresses the root cause by correcting the stride calculation to properly handle the integer overflow condition, ensuring that the bytes_per_line value accurately reflects the actual memory requirements for the image data being processed.
Organizations utilizing ImageMagick should prioritize immediate deployment of the patched versions to mitigate this vulnerability, particularly in environments where untrusted image files are processed automatically. The vulnerability's impact is amplified in web applications and content management systems where automatic image conversion is a common feature, making these environments prime targets for exploitation. Security teams should also consider implementing additional safeguards such as file type validation and automated scanning for malicious image files to provide defense-in-depth against potential exploitation attempts. Regular security assessments of image processing pipelines and monitoring for unusual memory access patterns can help detect potential exploitation attempts before they result in successful attacks.