Stack-based buffer overflow in Vim - CVE-2026-28422

Detailed vulnerability description

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

The vulnerability exists due to a boundary error within the build_stl_str_hl() function. A remote unauthenticated attacker can trick the victim into opening a specially crafted file, trigger stack-based buffer overflow and execute arbitrary code on the target system.

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

How to mitigate CVE-2026-28422

Sources

• https://github.com/vim/vim/security/advisories/GHSA-gmqx-prf2-8mwf
• https://github.com/vim/vim/commit/4e5b9e31cb7484ad156f