CVE-2026-59956

OpenImageIO: Heap-buffer-overread in IffInput::readimg() when ZBUFFER flag is set

MEDIUM
6.1
CVSS Score
Published: September 18, 2026 at 03:33 PM UTC
Updated: September 29, 2026 at 06:56 PM UTC
2 products affected across 2 vendorsOpenImageIOOpenImageIO

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Severity
MEDIUM6.1
Exploit prediction
EPSS 0.2%
SSVC
PoC

Description

OpenImageIO is a toolset for reading, writing, and manipulating image files of any image file format relevant to VFX / animation. Prior to 3.0.20.0, 3.1.15.0, and 3.2.0.3-beta1, An uncompressed 16-bit iff image with a z-buffer makes iffinput::readimg() allocate a temporary scanline from m_header.rgba_count but copy from it using m_header.pixel_bytes(), whose stride also includes z-buffer bytes. the oversized memcpy reads beyond the temporary heap buffer and copies adjacent memory into the output image, resulting in a crash or disclosure of adjacent heap data. The affected implementation is identified by src/iff.imageio/iffinput.cpp, IffInput::readimg(), m_header.rgba_count, and m_header.pixel_bytes(), which define the relevant source path, functions, state, and trigger. This issue is fixed in versions 3.0.20.0, 3.1.15.0, and 3.2.0.3-beta1.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 3.0.20.03.1.0.0 ≤ v ≤ 3.1.15.03.2.0.0 dev3.2.0.2 dev
Affected range stops below 3.0.20.0, so it looks safe — our inference, not a vendor statement
v < 3.0.20.0v < 3.1.15.0v < 3.2.0.3-beta1
Affected range stops below 3.0.20.0, so it looks safe — our inference, not a vendor statement
Affected range stops below 3.1.15.0, so it looks safe — our inference, not a vendor statement
Affected range stops below 3.2.0.3-beta1, so it looks safe — our inference, not a vendor statement

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.1MEDIUMGitHub_M
Attack Vector
LOCAL
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-125

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