A buffer overflow was found in the way GNU Screen before 4.8.0 treated the special escape OSC 49. Specially crafted output, or a special program, could corrupt memory and crash Screen or possibly have unspecified other impact.
https://www.openwall.com/lists/oss-security/2020/02/06/3
https://security.gentoo.org/glsa/202003-62
https://lists.gnu.org/archive/html/screen-devel/2020-02/msg00007.html