CVE-2026-26981

A flaw was found in OpenEXR. A remote attacker could exploit a heap-buffer-overflow vulnerability in the istream_nonparallel_read function by tricking a user into opening a specially crafted EXR file. This occurs when a signed integer subtraction results in a negative value that is then converted to a large unsigned size, leading to an out-of-bounds read during a memory copy operation. Successful exploitation of this vulnerability could lead to a denial of service.

The vulnerable code was introduced in OpenEXR 3.3.0 via commit https://github.com/AcademySoftwareFoundation/openexr/commit/c3e212e9c76c4d174f5624564f9103dc49ca1fd8.

OpenEXR 1.x (shipped in RHEL 6 and RHEL 7) and OpenEXR 2.x (shipped in RHEL 8) do not include the affected context implementation and are therefore not impacted. RHEL 9, RHEL 10 and RHIVOS-2 ship OpenEXR 3.1.x versions, which predate the introduction of the vulnerable code path and are also not affected.

Aditionally, Starting with OpenEXR 3.x, IlmBase was split out into a separate project named Imath. Imath provides math and numerical types, while OpenEXR contains all EXR file parsing logic.

This vulnerability exists within OpenEXR’s file parsing logic and does not affect the separate IlmBase or Imath libraries, which contain only mathematical and utility components and no file decoding functionality

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.