Null-dereference READ in Imf_2_5::Header::operator
External References: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=25740
Created OpenEXR tracking bugs for this issue: Affects: fedora-all [bug 1939175]
Upstream patch: https://github.com/AcademySoftwareFoundation/openexr/commit/25e9515b06a6bc293d871622b8cafaee7af84e0f
*** Bug 1939155 has been marked as a duplicate of this bug. ***