An out-of-bounds write vulnerability was found in Vim's vim_regsub_both() function in the src/regexp.c file. The flaw can open a command-line window from a substitute expression when a text or buffer is locked. This flaw allows an attacker to trick a user into opening a specially crafted file, triggering an out-of-bounds write that causes an application to crash, possibly reading and modifying some amount of memory contents.