CVE-2025-26603 Information

Description

Vim is a greatly improved version of the good old UNIX editor Vi. Vim allows to redirect screen messages using the :redir ex command to register variables and files. It also allows to show the contents of registers using the :registers or :display ex command. When redirecting the output of :display to a register Vim will free the register content before storing the new content in the register. Now when redirecting the :display command to a register that is being displayed Vim will free the content while shortly afterwards trying to access it which leads to a use-after-free. Vim pre 9.1.1115 checks in the ex_display() function that it does not try to redirect to a register while displaying this register at the same time. However this check is not complete and so Vim does not check the + and registers (which typically donate the X11/clipboard registers and when a clipboard connection is not possible will fall back to use register 0 instead. In Patch 9.1.1115 Vim will therefore skip outputting to register zero when trying to redirect to the clipboard registers or +. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Reference

https://github.com/vim/vim/commit/c0f0e2380e5954f4a52a131bf6b8 https://github.com/vim/vim/security/advisories/GHSA-63p5-mwg2-787v