CVE-2026-55892

Description

Vim is an open source, command line text editor. Prior to 9.2.0662, the dump_prefixes() function in src/spell.c walks a spell-file prefix trie iteratively with a depth counter while dumping the prefixes that apply to a word. The counter is bounded only by the trie structure itself; it is never checked against the size of the fixed MAXWLEN-element stack arrays it indexes (prefix[], arridx[], curi[]). A crafted .spl file, loaded when the user dumps the word list, can drive the descent arbitrarily deep, so the function writes past the end of those arrays. This is a stack out-of-bounds write that corrupts the call frame and crashes the editor. This vulnerability is fixed in 9.2.0662.

References

• https://github.com/vim/vim/commit/8325b193bba5f01e7a7d8241f
• https://github.com/vim/vim/releases/tag/v9.2.0662
• https://github.com/vim/vim/security/advisories/GHSA-qm9w-fmpj-879h