# CVE-2026-59956: OpenImageIO heap buffer over-read in IFF image parsing

Source: https://junglewise.ai/threats/cve-2026-59956-openimageio-is-a-toolset-for-reading-writing-and-manipulating  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-18. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-59956 · Severity: medium · CVSS 6.1 · Published 2026-09-18

OpenImageIO is a widely-used image processing library for VFX and animation workflows. A heap buffer over-read vulnerability in IFF image file parsing can cause application crashes or leak sensitive data from adjacent memory when processing specially crafted 16-bit IFF images with z-buffers, potentially exposing confidential information from the rendering process.

Technologies: [Academy Software Foundation OpenImageIO](https://junglewise.ai/threats/technologies/openimageio). Vendors: [Academy Software Foundation](https://junglewise.ai/threats/vendors/academy-software-foundation).

## Quick answers

**Is CVE-2026-59956 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-59956 being exploited in the wild.

**How severe is CVE-2026-59956?** Medium severity, with a CVSS score of 6.1, published 18 September 2026.

**Which products and versions are affected?** Academy Software Foundation OpenImageIO prior to 3.0.20.0, 3.1.15.0, and 3.2.0.3-beta1.

**Is there a fix for CVE-2026-59956?** A patch was published on 2026-06-27: Fix merged in commit f01bd16 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-59956 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-59956?** Check whether you run Academy Software Foundation OpenImageIO at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A buffer size mismatch in iffinput.cpp's readimg() function allocates a temporary scanline buffer based on rgba_count but copies data using pixel_bytes() stride, which includes z-buffer bytes for 16-bit uncompressed IFF images. This causes memcpy to read beyond the allocated buffer. The vulnerability requires opening a malicious IFF file and affects versions prior to 3.0.20.0, 3.1.15.0, and 3.2.0.3-beta1.

## Affected products

- Academy Software Foundation OpenImageIO prior to 3.0.20.0, 3.1.15.0, and 3.2.0.3-beta1

## Timeline

- 2026-09-18: disclosed: CVE-2026-59956 published
- 2026-06-27: patched: Fix merged in commit f01bd16

## References

- [https://github.com/AcademySoftwareFoundation/OpenImageIO/commit/f01bd16764b2a06f372899e3e302280a7f9c8c02](https://github.com/AcademySoftwareFoundation/OpenImageIO/commit/f01bd16764b2a06f372899e3e302280a7f9c8c02)
- [https://github.com/AcademySoftwareFoundation/OpenImageIO/pull/5251](https://github.com/AcademySoftwareFoundation/OpenImageIO/pull/5251)

## Related threats

- [OpenImageIO integer overflow in Cineon codec scanline buffer](https://junglewise.ai/threats/cve-2026-113681-openimageio-before-3-0-20-0-3-1-x-before-3-1-15-0-and-3-2-x)
- [OpenImageIO heap overflow in TIFF CMYK decoding](https://junglewise.ai/threats/cve-2026-67549-openimageio-is-a-toolset-for-reading-writing-and-manipulating)
- [OpenImageIO use-after-scope in multithreaded TIFF decompression](https://junglewise.ai/threats/cve-2026-65970-openimageio-is-a-toolset-for-reading-writing-and-manipulating)
- [OpenImageIO integer overflow in GIF palette splitting](https://junglewise.ai/threats/cve-2026-65969-openimageio-is-a-toolset-for-reading-writing-and-manipulating)
- [OpenImageIO heap overflow in cineon image parsing](https://junglewise.ai/threats/cve-2026-63638-openimageio-is-a-toolset-for-reading-writing-and-manipulating)