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.
History

Mon, 06 Apr 2026 15:30:00 +0000

Type Values Removed Values Added
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.
Title OpenEXR has a signed integer overflow (undefined behavior) in undo_pxr24_impl may allow bounds-check bypass in PXR24 decompression
Weaknesses CWE-190
CWE-787
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-04-06T15:22:40.198Z

Reserved: 2026-03-27T13:43:14.370Z

Link: CVE-2026-34380

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-04-06T16:16:35.400

Modified: 2026-04-06T16:16:35.400

Link: CVE-2026-34380

cve-icon Redhat

No data.