CVE-2026-52859

Name of the Vulnerable Software and Affected Versions Vim versions prior to 9.2.0565

Description The update snapshot() function in src/terminal.c copies the visible terminal screen into the scrollback buffer during a snapshot. The process involves iterating through the chars[] array of each screen cell without an upper bound, relying solely on a NUL terminator to stop. When a cell fills all VTERM MAX CHARS PER CELL (6) slots—consisting of a base character and five combining marks—the bundled libvterm returns the array without a terminating NUL. This causes the loop to read past the fixed six-element array and append out-of-bounds values to a buffer reserved for only six characters. A program rendering output inside a :terminal window can trigger this behavior using a short byte sequence, resulting in a crash.

Recommendations Update to version 9.2.0565.