Vim up to 9.2.661 src/spell.c dump_prefixes prefix[] out-of-bounds write

Summaryinfo

A vulnerability classified as critical was found in Vim up to 9.2.661. This vulnerability affects the function dump_prefixes of the file src/spell.c. The manipulation of the argument prefix[] results in out-of-bounds write. This vulnerability is identified as CVE-2026-55892. The attack can be executed remotely. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as critical, was found in Vim up to 9.2.661. Affected is the function dump_prefixes of the file src/spell.c. The manipulation of the argument prefix[] with an unknown input leads to a out-of-bounds write vulnerability. CWE is classifying the issue as CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. This is going to have an impact on availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-55892 since 06/17/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit.

Upgrading to version 9.2.0662 eliminates this vulnerability.

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Productinfo

Type

• Word Processing Software

Name

• Vim

Version

• 9.2.661

License

• open-source

Website

• Product: https://github.com/vim/vim/

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