Bug 2538937 (CVE-2026-63638)

Summary: CVE-2026-63638 OpenImageIO: OpenImageIO: Memory corruption via crafted Cineon image
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: high    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in OpenImageIO. A remote attacker could exploit this vulnerability by providing a specially crafted Cineon image file. This crafted file, when processed, can lead to a heap out-of-bounds write due to an invalid bit depth declaration, resulting in memory corruption. This could potentially allow for arbitrary code execution or a denial of service.
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Bug Depends On: 2539188, 2539191, 2539193    
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Description OSIDB Bzimport 2026-09-22 21:44:25 UTC 
OpenImageIO is a toolset for reading, writing, and manipulating image files of any image file format relevant to VFX / animation. Prior to 3.0.21.0, 3.1.16.0, and 3.2.0.3-beta1, A crafted cineon image can declare unsupported component bit depth 26. cineoninput::open() maps it to a 32-bit imagespec, but libcineon maps the unsupported depth to an 8-byte value, so cineoninput::read_native_scanline() causes attacker-controlled data to be written beyond the 4-byte-per-pixel caller buffer, resulting in a heap out-of-bounds write and memory corruption. The affected implementation is identified by src/cineon.imageio/cineoninput.cpp, CineonInput::open(), CineonInput::read_native_scanline(), ComponentDataSize(), bit depth 26, and ImageSpec, which define the relevant source path, functions, state, and trigger. This issue is fixed in versions 3.0.21.0, 3.1.16.0, and 3.2.0.3-beta1.