CVE-2026-55892: vim Out-of-bounds Write

Vulnerability summary

CVE-2026-55892 is a medium (CVSS 5.5) Out-of-bounds Write vulnerability in vim. EPSS estimates a 0.12% chance of exploitation in the next 30 days, higher than 1.7% 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 9.2.0662, 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.

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