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Vulnerability · Published Sep 18, 2026 · Assigned by GitHub_M

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

Medium 6.1

In plain English

A medium-severity out-of-bounds read in OpenImageIO from AcademySoftwareFoundation. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 10% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.1Medium
Exploit odds (30 days)0.2%top 89.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12openimageiono fix listedDEBIAN-CVE-2026-59956
Debian:13openimageiono fix listedDEBIAN-CVE-2026-59956
Debian:14openimageio3.1.18.0+dfsg-2DEBIAN-CVE-2026-59956
Ubuntu:22.04:LTSopenimageiono fix listedUBUNTU-CVE-2026-59956
Ubuntu:26.10openimageiono fix listedUBUNTU-CVE-2026-59956

Affected products (as reported)

VendorProductVersions
AcademySoftwareFoundation OpenImageIO < 3.0.20.0>= 3.1.0.0, < 3.1.15.0>= 3.2.0.0-dev, < 3.2.0.3-beta1

Weakness: CWE-125 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H

References