libESMTP through 1.0.6 mishandles domain copying into a fixed-size buffer in ntlm_build_type_2 in ntlm/ntlmstruct.c, as demonstrated by a stack-based buffer over-read.
https://web.archive.org/web/20190528215510/http://brianstafford.info/libesmtp/
https://github.com/Kirin-say/Vulnerabilities/blob/master/Stack_Overflow_in_libesmtp.md