rxvt-unicode 9.22, rxvt 2.7.10, mrxvt 0.5.4, and Eterm 0.9.7 allow (potentially remote) code execution because of improper handling of certain escape sequences (ESC G Q). A response is terminated by a newline.
cvs.schmorp.de/rxvt-unicode/Changes?view=log
cvs.schmorp.de/rxvt-unicode/src/command.C?r1=1.582&r2=1.583
git.enlightenment.org/apps/eterm.git/log/
lists.debian.org/debian-lts-announce/2021/05/msg00026.html
lists.debian.org/debian-lts-announce/2021/06/msg00010.html
lists.debian.org/debian-lts-announce/2021/06/msg00011.html
lists.debian.org/debian-lts-announce/2021/06/msg00012.html
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6RFMU5YXXNYYVA7G2DAHRXXHO6JKVFUT/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AO52OLNOOKOCZSJCN3R7Q25XA32BWNWP/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DUV4LDVZVW7KCGPAMFZD4ZJ4FVLPOX4C/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NZWGE2RJONBEHSPCBUAW72NTRTIFKZAX/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SLPVEPBH37EBR4R54RMC6GD33J37HJXD/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UXAKO6N6NKTR6Z6KVAPEXSZQMRU52SGA/
packetstormsecurity.com/files/162621/rxvt-2.7.0-rxvt-unicode-9.22-Code-Execution.html
security.gentoo.org/glsa/202105-17
security.gentoo.org/glsa/202209-07
sourceforge.net/projects/materm/files/mrxvt%20source/
sourceforge.net/projects/rxvt/files/rxvt-dev/
www.openwall.com/lists/oss-security/2017/05/01/20
www.openwall.com/lists/oss-security/2021/05/17/1