CVE-2026-59956: OpenImageIO: Heap-buffer-overread in IffInput::readimg() when ZBUFFER flag is set

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-09-18 · updated 2026-09-29
Weakness: CWE-125

Description

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.

Affected products

OpenImageIO Project OpenImageIO: before 3.0.20.0; from 3.1.0.0 through 3.1.15.0; 3.2.0.0-dev, 3.2.0.2-dev — fixed in 3.0.20.0

How to fix

Upgrade to a fixed version: OpenImageIO Project OpenImageIO 3.0.20.0. Check the vendor advisory for mitigations.

References

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