Bug 2538723 (CVE-2026-59956)

Summary: CVE-2026-59956 OpenImageIO: OpenImageIO: Heap-buffer-overread leads to information disclosure or denial of service when processing IFF images.
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in OpenImageIO. When processing an uncompressed 16-bit IFF (Image File Format) image with a z-buffer, the `iffinput::readimg()` function allocates a temporary scanline buffer that is smaller than required. This leads to an oversized memory copy operation that reads beyond the allocated heap buffer. A local attacker could provide a specially crafted IFF image, potentially causing a crash (Denial of Service) or disclosing sensitive adjacent heap data.
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Bug Depends On: 2539166, 2539167, 2539168    
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Description OSIDB Bzimport 2026-09-22 20:10:45 UTC 
OpenImageIO is a toolset for reading, writing, and manipulating image files of any image file format relevant to VFX / animation. Prior to 3.0.20.0, 3.1.15.0, and 3.2.0.3-beta1, An uncompressed 16-bit iff image with a z-buffer makes iffinput::readimg() allocate a temporary scanline from m_header.rgba_count but copy from it using m_header.pixel_bytes(), whose stride also includes z-buffer bytes. the oversized memcpy reads beyond the temporary heap buffer and copies adjacent memory into the output image, resulting in a crash or disclosure of adjacent heap data. The affected implementation is identified by src/iff.imageio/iffinput.cpp, IffInput::readimg(), m_header.rgba_count, and m_header.pixel_bytes(), which define the relevant source path, functions, state, and trigger. This issue is fixed in versions 3.0.20.0, 3.1.15.0, and 3.2.0.3-beta1.