SB2026030326 - Heap-based buffer overflow in Vim

Description

This security bulletin contains information about 1 vulnerability.

1) Heap-based buffer overflow (CVE-ID: CVE-2026-28420)

CWE-ID: CWE-122 - Heap-based Buffer Overflow

CVSSv4: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error within the handle_pushline() function in src/terminal.c processing maximum combining characters from Unicode supplementary planes. A remote attacker can trick the victim into copying a specially crafted string into the :terminal buffer, trigger a heap-based buffer overflow and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Remediation

Install update from vendor's website.

References

• https://github.com/vim/vim/security/advisories/GHSA-rvj2-jrf9-2phg
• https://github.com/vim/vim/commit/bb6de2105b160e729c34063