CVE-2026-63638: academysoftwarefoundation openimageio Out-of-bounds Write

Vulnerability summary

CVE-2026-63638 is a high (CVSS 8.3) Out-of-bounds Write vulnerability in academysoftwarefoundation openimageio. EPSS estimates a 0.46% chance of exploitation in the next 30 days, higher than 38.9% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 18-09-2026
   PublishedVulnerability first disclosed.
2. 22-09-2026
   Last modifiedVulnerability information updated.

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 crafted cineon image can declare unsupported component bit depth 26. cineoninput::open() maps it to a 32-bit imagespec, but libcineon maps the unsupported depth to an 8-byte value, so cineoninput::read_native_scanline() causes attacker-controlled data to be written beyond the 4-byte-per-pixel caller buffer, resulting in a heap out-of-bounds write and memory corruption. The affected implementation is identified by src/cineon.imageio/cineoninput.cpp, CineonInput::open(), CineonInput::read_native_scanline(), ComponentDataSize(), bit depth 26, and ImageSpec, 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.

• CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.