OpenEXR is the reference implementation and specification for the EXR image format, widely used in the motion picture industry

Overview

OpenEXR is the reference implementation and specification for the EXR image format, widely used in the motion picture industry. Versions 3.3.0 through 3.3.12 and 3.4.0 through 3.4.13 contain a heap buffer overflow in PyOpenEXR triggered by a channel-name key collision between literal and prefixed RGB channels. When separate_channels=false, PyOpenEXR maps each physical channel name through channelNameToRGBA() and coalesces the results into a shared RGB array. A crafted flat scanline EXR that contains both a literal channel such as left and prefixed channels such as left.R, left.G, and left.B causes these names to collide, so the wrapper reuses an undersized two-dimensional NumPy array for the coalesced RGB slices and writes out of bounds when OpenEXR.File(path) decodes the pixels. This issue is fixed in versions 3.3.13 and 3.4.14.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

Vendor advisories

• Red Hat VEX · Important · updated 2026-09-18 · vex