What’s Vulnerable › Vulnerabilities

CVE-2026-34378: OpenEXR has a signed integer overflow in generic_unpack() when parsing EXR files with crafted negative dataWindow.min.x

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-04-06 · updated 2026-10-26
• Weakness: CWE-190

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 products

• AcademySoftwareFoundation openexr: from 3.4.0 before 3.4.9 — fixed in 3.4.9

How to fix

Upgrade to a fixed version: AcademySoftwareFoundation openexr 3.4.9. Check the vendor advisory for mitigations.

References

• https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.9
• https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-v76p-4qvv-vh4g

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