OpenEXR Makes Use of Uninitialized Memory

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. In versions 3.3.0 through 3.3.5 and 3.4.0 through 3.4.2, while fuzzing `openexr_exrcheck_fuzzer`, Valgrind reports a conditional branch depending on uninitialized data inside `generic_unpack`. This indicates a use of uninitialized memory. The issue can result in undefined behavior and/or a potential crash/denial of service. Versions 3.3.6 and 3.4.3 fix the issue.