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Vulnerability · Published Sep 18, 2026 · Assigned by GitHub_M

CVE-2026-63638OpenImageIO: Cineon invalid bit depth heap out-of-bounds write

High 8.3

In plain English

A high-severity out-of-bounds write in OpenImageIO from AcademySoftwareFoundation. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.3High
Exploit odds (30 days)0.5%top 59.6% 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 3.0.21.0, 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12openimageiono fix listedDEBIAN-CVE-2026-63638
Debian:13openimageiono fix listedDEBIAN-CVE-2026-63638
Debian:14openimageio3.1.18.0+dfsg-2DEBIAN-CVE-2026-63638
Ubuntu:22.04:LTSopenimageiono fix listedUBUNTU-CVE-2026-63638
Ubuntu:26.10openimageiono fix listedUBUNTU-CVE-2026-63638

Affected products (as reported)

VendorProductVersions
AcademySoftwareFoundation OpenImageIO < 3.0.21.0>= 3.1.0.0, < 3.1.16.0>= 3.2.0.0-dev, < 3.2.0.3-beta1

Weakness: CWE-787 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:H

References