libyara/lexer.l in YARA 3.5.0 allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a crafted rule that is mishandled in the yy_get_next_buffer function.
https://github.com/VirusTotal/yara/commit/3119b232c9c453c98d8fa8b6ae4e37ba18117cd4