CVE-2024-43374 - Use-After-Free Error in UNIX Editor Vim Prior to Version 9.1.0678

A recently discovered vulnerability, identified as CVE-2024-43374, affects the UNIX editor Vim prior to version 9.1.0678. This vulnerability is a use-after-free error in the argument list handling that can potentially lead to a crash in Vim. Although the impact of this vulnerability is low, it is essential to educate users about its existence, exploitation, and methods to mitigate it.

Description

The core of the vulnerability revolves around argument list handling in Vim. When adding a new file to the argument list, it triggers Buf* autocommands. If, during this process, the buffer that was just opened is closed (including the window where it is shown), the window structure containing the reference to the argument list will be freed. After the autocommands are completed, the references to the window and argument list are no longer valid, leading to a use-after-free error.

Exploit Details

The exploitation of this vulnerability requires the user to either intentionally add unusual autocommands that wipe a buffer during its creation (manually or by sourcing a malicious plugin). Although this is unlikely to happen, it may potentially crash Vim.

Code Snippet Example

" vulnerable.vimrc
augroup my_autocmd
    au!
    au BufAdd * bwipeout! # Wiping the buffer during creation
augroup END

" To simulate the exploit, run: vim -u vulnerable.vimrc a.txt b.txt

The following links provide more information about the vulnerability and its fix

- Vim Mailing List Entry - Use-after-free error
- Vim Patch v9.1.0678 - Fixing the vulnerability

Mitigation

The fix for this vulnerability is already available in Vim patch v9.1.0678. Therefore, users should upgrade Vim to this version or any subsequent release to secure their editor against this specific issue.

Conclusion

Although the impact of CVE-2024-43374 is low, it serves as a reminder to be vigilant about potential security issues with our tools and the importance of updating applications to their latest versions. By migrating to Vim 9.1.0678 or a newer version, users can ensure their UNIX editor is not susceptible to this particular vulnerability.

Timeline

Published on: 08/16/2024 02:15:17 UTC
Last modified on: 08/19/2024 13:00:23 UTC