CVE-2026-34378: Integer Overflow in OpenEXR 3.4.0-3.4.8

An attacker could exploit this Integer Overflow vulnerability by crafting a malicious EXR file with a specifically engineered dataWindow.min.x value. This manipulation triggers an oversized image width calculation, ultimately resulting in a signed integer overflow during a multiplication operation. The resulting SIGILL signal causes the OpenEXR process to crash, potentially disrupting image processing pipelines and related workflows. While not directly leading to data exfiltration or remote code execution, the denial-of-service impact can be significant, especially in critical motion picture production environments where OpenEXR is integral to image storage and manipulation. The vulnerability's reliance on file parsing makes it a potential target for supply chain attacks, where malicious EXR files could be introduced into legitimate workflows.

1. Reserved2026-03-27
2. Published2026-04-06
3. Modified2026-04-07
4. EPSS updated2026-04-14

The primary mitigation for CVE-2026-34378 is to upgrade to OpenEXR version 3.4.9 or later, which includes the necessary bounds check to prevent the integer overflow. If upgrading is not immediately feasible, consider implementing input validation on EXR files before processing them. This could involve checking the dataWindow attribute for excessively large or negative values. While a WAF or proxy cannot directly mitigate this vulnerability, they can be configured to block suspicious EXR files based on file size or other characteristics. There are no specific Sigma or YARA rules readily available for this vulnerability, but monitoring for SIGILL signals originating from OpenEXR processes could indicate exploitation.