Buffer overflow in Vim

CVE-2026-28420

Vim is an open source, command line text editor. Prior to version 9.2.0076, a heap-based buffer overflow WRITE and an out-of-bounds READ exist in Vim's terminal emulator when processing maximum combining characters from Unicode supplementary planes. Version 9.2.0076 fixes the issue.

Vulnerability class: Buffer Overflow

Published · last modified .

CVSS v3 metric

CVSS v3 base score 4.4 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L.

EPSS exploit prediction

EPSS: 0.002 (7.8th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 8th percentile — 7.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-28420: held from 0.002 to 0.002.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

Affected products

  • Vim — versions < 9.2.0076

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-28420?
CVE-2026-28420 is a medium-severity vulnerability in Vim, classified under Heap-based Buffer Overflow. CVSS score: 4.4/10. Published 2026-02-27.
How severe is CVE-2026-28420?
Medium severity. CVSS v3 base score is 4.4 out of 10.