Out-of-bounds Read in Vim
CVE-2026-52859
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H.
EPSS exploit prediction
EPSS: 0.006 (43.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 44th percentile — 43.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.006 · change: +0.002
Affected products
- Vim — versions < 9.2.0565
Weakness classification (CWE)
References
- github.com/vim/vim/commit/63680c6d3d52477817b49cd1a66e7aabe8a7aa19 (Patch)
- github.com/vim/vim/releases/tag/v9.2.0565 (Release Notes)
- github.com/vim/vim/security/advisories/GHSA-47gw-8gc3-mgcm (Vendor Advisory)
Frequently asked questions
- What is CVE-2026-52859?
- CVE-2026-52859 is a high-severity vulnerability in Vim, classified under Out-of-bounds Read. CVSS score: 8.2/10. Published 2026-06-11.
- How severe is CVE-2026-52859?
- High severity. CVSS v3 base score is 8.2 out of 10.