CVE-2025-0725: gzip integer overflow

The current master branch of [libcurl](https://github.com/curl/curl/tree/7e814c8717939393d4436d75f5f0c3ffa98c8c53) contains a vulnerability in [lib/content_encoding.c](https://github.com/curl/curl/blob/7e814c8717939393d4436d75f5f0c3ffa98c8c53/lib/content_encoding.c#L539) that allows a malicious …

    z->avail_in += (uInt) nbytes;
    z->next_in = Curl_saferealloc(z->next_in, z->avail_in);
    if(!z->next_in) {
      return exit_zlib(data, z, &zp->zlib_init, CURLE_OUT_OF_MEMORY);
    }
    /* Append the new block of data to the previous one */
    memcpy(z->next_in + z->avail_in - nbytes, …