CVE-2026-34378: academysoftwarefoundation openexr Integer Overflow or Wraparound

Vulnerability summary

CVE-2026-34378 is a medium (CVSS 6.5) Integer Overflow or Wraparound vulnerability in academysoftwarefoundation openexr. EPSS estimates a 0.39% chance of exploitation in the next 30 days, higher than 31.6% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 06-04-2026
   PublishedVulnerability first disclosed.
2. 07-04-2026
   Last modifiedVulnerability information updated.

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.

• CWE-190Integer Overflow or WraparoundThe product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.