What’s Vulnerable › Vulnerabilities

CVE-2026-55892: Vim: Out-of-bounds Write in Spell File Prefix Dump

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-25 · updated 2026-06-26
• Weakness: CWE-787

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.

Affected products

• vim/vim: before 9.2.0662 — fixed in 9.2.0662

How to fix

Upgrade to a fixed version: vim/vim 9.2.0662. Check the vendor advisory for mitigations.

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

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