Is CVE-2026-34378 actively exploited?

CVE-2026-34378 has no public evidence of in-the-wild exploitation as of 2026-04-07.

What is the CVSS score for CVE-2026-34378?

CVE-2026-34378 has a CVSS score of 6.5 (MEDIUM severity). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

How do I patch CVE-2026-34378?

Patch guidance is available from openexr security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2026-34378.

CVE-2026-34378 - remediation guidance & executive summary

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.

CVSS Metrics

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Attack Vector: network
Complexity: low
Privileges: none
User Action: required
Scope: unchanged
Confidentiality: none
Integrity: none
Availability: high
Weaknesses: CWE-190 · Integer Overflow

Metadata

Primary Vendor: OPENEXR
Published: 4/6/2026
Last Modified: 4/7/2026
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.

Affected Products

openexr : openexr

Remediation Guidance

Executive Summary

Cite this page

CVE-2026-34378. CVEDatabase.com. Retrieved 1 May 2026. https://cvedatabase.com/cve/CVE-2026-34378

View on NIST NVD

CVE-2026-34378 vulnerability