ASA-2019-00043 – curl: SMTP end-of-response out-of-bounds read

libcurl contains a heap out-of-bounds read in the code handling the end-of-response for SMTP. If the buffer passed to smtp_endofresp() isn't NUL terminated and contains no character ending the parsed number, and len is set to 5, then the strtol() call reads beyond the allocated buffer. The read contents will not be returned to the caller.