A workspace buffer overflow vulnerability was found in the .upper()
and .lower() string type methods of VCL.
This can be used as a remote denial of service (DoS) vector to make
the child process segfault or assert, and then restart.
Effectively exploiting this vulnerability requires prior knowledge
about the VCL in use and the ability to craft a request that contains a
string that is long enough to fill the remaining workspace at the call
site while staying under the different request size limits
(http_req_size, http_req_hdr_len, ..etc).