Vulnerability · Published Apr 6, 2026 · Assigned by GitHub_M
CVE-2026-34378OpenEXR has a signed integer overflow in generic_unpack() when parsing EXR files with crafted negative dataWindow.min.x
Medium 6.5
In plain English
A medium-severity integer overflow in openexr from AcademySoftwareFoundation. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 20% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.22 | openexr | 3.3.11-r0 | ALPINE-CVE-2026-34378 |
| Alpine:v3.23 | openexr | 3.4.13-r0 | ALPINE-CVE-2026-34378 |
| Alpine:v3.24 | openexr | 3.4.10-r0 | ALPINE-CVE-2026-34378 |
| Debian:14 | openexr | 3.4.14-0.1 | DEBIAN-CVE-2026-34378 |
| Ubuntu:26.10 | openexr | no fix listed | UBUNTU-CVE-2026-34378 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| AcademySoftwareFoundation | openexr | >= 3.4.0, < 3.4.9 |
Weakness: CWE-190 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H