CVE-2026-34378: OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for…
CVE-2026-34378 · Severity: medium · CVSS 6.5 · Published 2026-04-06
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.
No. Junglewise Threat Intelligence has no report of CVE-2026-34378 being exploited in the wild.
How severe is CVE-2026-34378?
Medium severity, with a CVSS score of 6.5, published 6 April 2026.
Which products and versions are affected?
Openexr. The advisory does not name versions.
Is there a fix for CVE-2026-34378?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
Am I affected by CVE-2026-34378?
Check whether you run Openexr. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.