lilypond-invoke-editor in LilyPond 2.19.80 does not validate strings before launching the program specified by the BROWSER environment variable, which allows remote attackers to conduct argument-injection attacks via a crafted URL, as demonstrated by a --proxy-pac-file argument, because the GNU Guile code uses the system Scheme procedure instead of the system* Scheme procedure. NOTE: this vulnerability exists because of an incomplete fix for CVE-2017-17523.