Executive brief
OpenEXR 3.4.14 contains a NULL Pointer Dereference in the C++ attribute parsing path. A specially crafted EXR file containing an unknown-type attribute with dataSize set to zero causes the parser to create an opaque attribute with a NULL packed_data pointer. The OpaqueAttribute constructor passes the NULL pointer to memcpy() without validating the zero-size condition, resulting in undefined behavior and process termination, leading to denial of service.