Medium [CVE-2026-59858] Arbitrary command execution via crafted tags file in C omni-completion

Vim is an open source, command line text editor. Prior to 9.2.0735, the C omni-completion script in runtime/autoload/ccomplete.vim interpolates the typeref: or typename: extension field of a tags entry, without escaping, into a:vimgrep pattern that is run through:execute.

Because:vimgrep honors the bar as a command separator, a crafted tag field can close the search pattern and append an arbitrary Ex command; opening a hostile.c file whose project tags file contains such an entry and invoking C omni-completion runs that command as the editing user. This issue is fixed in version 9.2.0735.

A command injection vulnerability in Vim's C omni-completion script allows an attacker to execute arbitrary commands if a user is tricked into opening a maliciously crafted tags file and manually invoking the autocomplete feature.

Exploitation requires a user to open a specially crafted C source file along with a malicious project tags file and then invoke C omni-completion. This limits the attack vector as it relies on specific user interaction and the presence of a hostile tags file, making it less likely to be exploited without user awareness.

Red Hat severity: Moderate — CVSS 6.5 (CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L). Weakness: CWE-94.