CVE-2026-34378

OpenEXR has a signed integer overflow in generic_unpack() when parsing EXR files with crafted negative dataWindow.min.x

MEDIUM
6.5
CVSS Score
Published: April 6, 2026 at 03:19 PM UTC
Updated: October 26, 2026 at 09:10 PM UTC
2 products affected across 2 vendorsOpenexrOpenexr

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.3%
SSVC
PoC

Description

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.4.0 to before 3.4.9, a missing bounds check on the dataWindow attribute in EXR file headers allows an attacker to trigger a signed integer overflow in generic_unpack(). By setting dataWindow.min.x to a large negative value, OpenEXRCore computes an enormous image width, which is later used in a signed integer multiplication that overflows, causing the process to terminate with SIGILL via UBSan. This vulnerability is fixed in 3.4.9.

Affected

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

3.4.0 ≤ v < 3.4.9
3.4.0 ≤ v < 3.4.9
Affected range stops below 3.4.9, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

x_refsource_MISCProductRelease Notes
Source: cverecord
https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.9

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

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

CVSS

6.5MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-190

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