Integer overflow in Academysoftwarefoundation Openexr
CVE-2026-34378
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.
Vulnerability class: Integer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (30.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 30th percentile — 30.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001
Affected products
- Academysoftwarefoundation Openexr — versions >= 3.4.0, < 3.4.9
- Openexr
Weakness classification (CWE)
References
- github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-v76p-4qvv… (Exploit, Vendor Advisory)
- github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.9 (Product, Release Notes)
Frequently asked questions
- What is CVE-2026-34378?
- CVE-2026-34378 is a medium-severity vulnerability in Academysoftwarefoundation Openexr, classified under Integer Overflow or Wraparound. CVSS score: 6.5/10. Published 2026-04-06.
- How severe is CVE-2026-34378?
- Medium severity. CVSS v3 base score is 6.5 out of 10.