use-after-free when closing buffers in Vim

Vulnerability Description

Vim is an open source, command line text editor. A use-after-free was found in Vim < 9.1.0764. When closing a buffer (visible in a window) a BufWinLeave auto command can cause an use-after-free if this auto command happens to re-open the same buffer in a new split window. Impact is low since the user must have intentionally set up such a strange auto command and run some buffer unload commands. However this may lead to a crash. This issue has been addressed in version 9.1.0764 and all users are advised to upgrade. There are no known workarounds for this vulnerability.

References

• https://github.com/vim/vim/security/advisories/GHSA-rj48-v4mq-j4vg
• https://github.com/vim/vim/commit/51b62387be93c65fa56bbabe1c3