Use-After-Free in SMB connection reuse (req->path dangling pointer after needle destruction)

A heap-use-after-free occurs in `smb_send_open()` at `lib/smb.c` when curl processes two SMB URLs targeting the same host. The function `smb_parse_url_path()` sets `req->path` as a non-owning pointer into `smbc->share` (connection-owned memory). During connection reuse, the needle connection is …

git clone https://github.com/curl/curl.git && cd curl
autoreconf -fi
./configure --with-openssl --enable-smb --without-libpsl
make CFLAGS="-fsanitize=address -g -O0 -fno-omit-frame-pointer" LDFLAGS="-fsanitize=address" -j$(nproc)