CVE-2026-63638 OpenImageIO: Cineon invalid bit depth heap out-of-bounds write
A crafted Cineon image triggers a heap out-of-bounds write in OpenImageIO, potentially allowing code execution or denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-63638?
CVE-2026-63638 is a high-severity memory corruption vulnerability in Openimageio Openimageio, published on 18 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
OpenImageIO is a toolset for reading, writing, and manipulating image files of any image file format relevant to VFX / animation. Prior to 3.0.21.0, 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.
Weakness: CWE-787
Which versions are affected by CVE-2026-63638?
It affects 1 product.
Products include Openimageio Openimageio.
How do I fix CVE-2026-63638?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-63638 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63638 exists.
Other vulnerabilities in Openimageio Openimageio
Sources
Also known as DEBIAN-CVE-2026-63638, GHSA-9hxv-jvgr-3x8g, UBUNTU-CVE-2026-63638.