What’s Vulnerable › Vulnerabilities

CVE-2026-55693: Vim: Out-of-bounds Write in Spell File Word Count

• Severity: high (CVSS 7.8 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 9.2.0653, the tree_count_words() function in src/spellfile.c fills in the word-count fields of a spell-file word trie by walking it iteratively with a depth counter. 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 (arridx[], curi[], wordcount[]). A crafted .spl/.sug file pair, loaded when the user invokes spell suggestion, 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 9.2.0653.

Affected products

• vim/vim: before 9.2.0653 — fixed in 9.2.0653

How to fix

Upgrade to a fixed version: vim/vim 9.2.0653. Check the vendor advisory for mitigations.

References

• https://github.com/vim/vim/commit/a80874d9b84a01040e3d1aef2d4a59e1934dafb7
• https://github.com/vim/vim/releases/tag/v9.2.0653
• https://github.com/vim/vim/security/advisories/GHSA-wgh4-64f7-q3jq

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