Vulnerability · Published Apr 6, 2026 · Assigned by GitHub_M
CVE-2026-34380OpenEXR has a signed integer overflow (undefined behavior) in undo_pxr24_impl may allow bounds-check bypass in PXR24 decompression
Medium 5.9
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 18% 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 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, a signed integer overflow exists in undo_pxr24_impl() in src/lib/OpenEXRCore/internal_pxr24.c at line 377. The expression (uint64_t)(w * 3) computes w * 3 as a signed 32-bit integer before casting to uint64_t. When w is large, this multiplication constitutes undefined behavior under the C standard. On tested builds (clang/gcc without sanitizers), two's-complement wraparound commonly occurs, and for specific values of w the wrapped result is a small positive integer, which may allow the subsequent bounds check to pass incorrectly. If the check is bypassed, the decoding loop proceeds to write pixel data through dout, potentially extending far beyond the allocated output buffer. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.22 | openexr | 3.3.11-r0 | ALPINE-CVE-2026-34380 |
| Alpine:v3.23 | openexr | 3.4.13-r0 | ALPINE-CVE-2026-34380 |
| Alpine:v3.24 | openexr | 3.4.10-r0 | ALPINE-CVE-2026-34380 |
| Debian:12 | openexr | no fix listed | DEBIAN-CVE-2026-34380 |
| Debian:13 | openexr | no fix listed | DEBIAN-CVE-2026-34380 |
| Debian:14 | openexr | 3.4.14-0.1 | DEBIAN-CVE-2026-34380 |
| Ubuntu:25.10 | openexr | no fix listed | UBUNTU-CVE-2026-34380 |
| Ubuntu:26.10 | openexr | no fix listed | UBUNTU-CVE-2026-34380 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| AcademySoftwareFoundation | openexr | >= 3.2.0, < 3.2.7>= 3.3.0, < 3.3.9>= 3.4.0, < 3.4.9 |
Weakness: CWE-190, CWE-787 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H
References
- https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-q3v8-hw4m-59w5 x_refsource_CONFIRM
- https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.2.7 x_refsource_MISC
- https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.3.9 x_refsource_MISC
- https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.9 x_refsource_MISC