SIGABRT on std::ifstream close

1I am currently working on a project of creating my own game in OpenGL. My problem is right now, that if I read a file, that my function reading that file results in a SIGABRT, because of something inside the std::ifstream deconstructor (more specifically in "std::basic_ifstream<char, std::char_traits<char> >::~basic_ifstream()"). This function previously worked for me, but suddenly stopped working.

My Goal is simple: A reliable implementation for reading a file to a char*. Multi threading is currently not my concern.

Here is my implementation of the file reading function.
It takes in a path, and should write the content of the file at that path into the out parameter.

#include <fstream>
#include <iostream>
#include <sstream>
#include <string>
#include <cstring>
#include <cassert>
#include "Utility.h"
char * Utility::readFile(const char* path,char*& out){
#ifndef NDEBUG
    std::cout<<"Getting file: "<<path<<"n";
#endif
    // Open the file, but freak out if not valid.
    std::ifstream file=std::ifstream(path);
    assert(file.good());
    if(!file.good())
    {
        throw std::runtime_error((std::string)"Couldn't open file for loading: "+path);
    }

    // Read the file contents into a char buffer.
    std::stringstream buffer;buffer << file.rdbuf();
    std::string fileContentsStr = buffer.str();
    out = new char[fileContentsStr.size()];
    strcpy(out,fileContentsStr.c_str());
    return out;
}

My code is located at C0D3-M4513R/OpenGlGame.
I already tried a minimal example, which is working and using the same compile flags (except linker flags). test.txt and test1.txt just contain some rubbish text generated by randomly hacking on my keyboard.

#include <cassert>
#include <fstream>
#include <iostream>
#include <sstream>
#include <string>
#include <cstring>

//This Function is the same as the one above!!!
char *readFile(const char *path, char *&out) {
#ifndef NDEBUG
    std::cout << "Getting file: " << path << "n";
#endif
    // Open the file, but freak out if not valid.
    std::ifstream file = std::ifstream(path);
    assert(file.good());
    if (!file.good()) {
        throw std::runtime_error((std::string) "Couldn't open file for loading: " + path);
    }

    // Read the file contents into a char buffer.
    std::stringstream buffer;
    buffer << file.rdbuf();
    //convert the stringstream to a string
    std::string fileContentsStr = buffer.str();
    //copy the contents of the string to a char array
    out = new char[fileContentsStr.size()];
    strcpy(out, fileContentsStr.c_str());
    //return char array address (which should be the same as the start?)
    return out;
}

int main() {
    //The programm started!
    std::cout << "Hello, World!" << std::endl;
    //Define a space for the contents of the file to live
    char *out;
    //Read the contents of a file
    out = readFile("test.txt", out);
    //Print contents of the file
    std::cout << out << std::endl;
    char *out1;
    //Read the contents of a file
    out1 = readFile("test1.txt", out1);
    //Print contents of the file
    std::cout << out1 << std::endl;
    return 0;
}