Greasemonkey before 0.3.5 allows remote web servers to (1) read arbitrary files via a GET request to a file:// URL in the GM_xmlhttpRequest API function, (2) list installed scripts using GM_scripts, or obtain sensitive information via (3) GM_setValue and GM_getValue.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.085
EPSS Ranking 92.0%