CVE-2026-52859: vim Out-of-bounds Read

Vulnerability summary

CVE-2026-52859 is a high (CVSS 8.2) Out-of-bounds Read vulnerability in vim. EPSS estimates a 0.30% chance of exploitation in the next 30 days, higher than 21.7% of scored vulnerabilities.

Timeline

1. 11-06-2026
   PublishedVulnerability first disclosed.
2. 11-06-2026
   Last modifiedVulnerability information updated.

Description

Vim is an open source, command line text editor. Prior to version 9.2.0565, the update_snapshot() function in src/terminal.c copies the visible terminal screen into the scrollback buffer when a snapshot is taken. For each screen cell it walks the cell's chars[] array with no upper bound, stopping only when it encounters a NUL terminator. When a cell legitimately fills all VTERM_MAX_CHARS_PER_CELL (6) slots — a base character plus five combining marks — the bundled libvterm returns the array without a terminating NUL, so the loop reads past the fixed six-element array and appends the out-of-bounds values to a buffer reserved for only six characters. A program whose output is rendered inside a :terminal window can trigger this with a short byte sequence and no Vim scripting, leading to a crash. This issue has been patched in version 9.2.0565.

• CWE-125Out-of-bounds ReadThe product reads data past the end, or before the beginning, of the intended buffer.