The check_connection function in sql_parse.cc in MySQL 4.0.x up to 4.0.26, 4.1.x up to 4.1.18, and 5.0.x up to 5.0.20 allows remote attackers to read portions of memory via a username without a trailing null byte, which causes a buffer over-read.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.622
EPSS Ranking 98.3%