CVE-2026-106063 in Red Hat
Summary
by MITRE • 10/06/2026
A heap-based buffer overflow was found in GIMP’s DICOM export plug-in. When exporting an image with extremely large width and height, the export path allocates a buffer using a 32-bit width * height (and bytes-per-pixel) product that can overflow. GEGL then writes the full uncompressed extent into the undersized buffer (CWE-787), after integer overflow in the allocation size
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Analysis
by VulDB Data Team • 10/08/2026
The vulnerability identified within GIMP’s DICOM export plug-in represents a critical memory safety failure rooted in improper boundary checking and arithmetic handling during image processing operations. Specifically, this flaw manifests as a heap-based buffer overflow where the application attempts to allocate memory for an uncompressed image extent based on dimensions provided by the user or input file. The core technical issue arises from the calculation of the required buffer size, which is derived by multiplying the width, height, and bytes-per-pixel values. Because these multiplications are performed using 32-bit integer arithmetic, they are susceptible to integer overflow when dealing with extremely large dimensions. If the product exceeds the maximum value representable by a signed or unsigned 32-bit integer, it wraps around to a significantly smaller positive number, leading the allocation routine to reserve far less memory than is actually required for storing the image data.
This arithmetic error directly facilitates CWE-787, which classifies out-of-bounds writes on heap memory. Once the undersized buffer is allocated via GEGL, the export process proceeds to write the full uncompressed extent of the image into this insufficiently sized region. Since the actual size of the image data exceeds the allocated capacity, subsequent write operations spill over the boundaries of the designated heap block. This overflow corrupts adjacent memory structures on the heap, potentially overwriting metadata such as allocation headers or pointers used by the memory allocator and other application components. The severity of this vulnerability is compounded by its potential to be triggered remotely if an attacker can craft a malicious DICOM file with specifically engineered dimensions that cause the integer overflow condition during export operations initiated by the victim user.
From an operational perspective, exploiting this heap-based buffer overflow could allow for arbitrary code execution under the context of the application process. By carefully crafting the payload within the overflowing data, an attacker may overwrite function pointers or exception handling structures to redirect program flow to malicious shellcode placed in adjacent memory regions. Alternatively, such corruption can lead to denial-of-service conditions through segmentation faults when the corrupted heap metadata is accessed during subsequent deallocation or reallocation events. The impact extends beyond immediate crash scenarios, as persistent heap corruption can destabilize the entire application environment, leading to unpredictable behavior and potential data loss for users working with large medical imaging files.
Mitigation strategies must address both the arithmetic vulnerability and the resulting memory safety issue. Developers should implement strict validation checks on image dimensions before performing any size calculations or buffer allocations. Utilizing 64-bit integer types for dimension multiplications can prevent the wrap-around behavior inherent in 32-bit arithmetic, ensuring that allocation sizes accurately reflect the true requirements of the data being processed. Additionally, incorporating bounds checking mechanisms within GEGL and the export plug-in would provide a secondary layer of defense against out-of-bounds writes. From a defensive standpoint, users should ensure their GIMP installations are updated to versions where this integer overflow has been patched with proper size validation logic. Security practitioners monitoring for exploitation attempts should look for abnormal memory allocation patterns or crashes associated with DICOM export operations involving unusually large image dimensions, aligning detection efforts with known attack vectors such as those categorized under CWE-190 for integer overflow and CWE-787 for buffer overflows.