logger.c in the logger plugin in WeeChat before 1.9.1 allows a crash via strftime date/time specifiers, because a buffer is not initialized.
https://weechat.org/news/98/20170923-Version-1.9.1-security-release/
https://weechat.org/download/security/
https://github.com/weechat/weechat/commit/f105c6f0b56fb5687b2d2aedf37cb1d1b434d556