CVE-2026-55693: vim Out-of-bounds Write

Vulnerability summary

CVE-2026-55693 is a high (CVSS 7.8) Out-of-bounds Write vulnerability in vim. EPSS estimates a 0.12% chance of exploitation in the next 30 days, higher than 1.9% of scored vulnerabilities.

Timeline

1. 25-06-2026
   PublishedVulnerability first disclosed.
2. 26-06-2026
   Last modifiedVulnerability information updated.

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.

• CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.