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MEDIUM

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

Published Jun 25, 2026

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

Remediation

Red Hat statement

This Moderate impact vulnerability in Vim's spell suggestion feature allows an attacker to cause a denial of service. By tricking a user into loading a specially crafted spell file and invoking spell suggestion, an out-of-bounds write can occur, leading to a crash of the editor. This requires user interaction and a malicious file, limiting its immediate exploitability.

Metrics

Weaknesses (2)

CWE-120

Classic Buffer Overflow

CWE-787

Out-of-bounds Write

References (7)

Change history (0)

No recorded changes yet.

Sources
CVE.org / MITRE
Status PUBLISHED
Assigner GitHub_M
Published Jun 25, 2026
Updated Jun 26, 2026
Reserved Jun 17, 2026
Link CVE-2026-55693
CISA Vulnrichment
Updated Jun 26, 2026
NVD
Status Analyzed
Modified Jun 26, 2026
Link CVE-2026-55693
Red Hat
Severity Moderate
Public date Jun 25, 2026
Links CVE-2026-55693 - Bugzilla