CVE-2026-55693

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

Published Jun 25, 2026 CVSS 4.0 · 5.7 Medium EPSS < 1% KEV · Not listed

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.

Analysis

Technical impact

The vulnerability is an out-of-bounds write in the spell-file word-count function. It allows a crafted .spl/.sug pair to cause Vim to write past the bounds of a stack array, corrupting the call frame and crashing the editor. This leads to a denial of service but does not provide remote code execution.

Affected Systems

The problem affects Vim versions earlier than 9.2.0653. Users of any operating system or architecture running an older Vim build and who load spell suggestions from untrusted files are potentially affected. The official vendor fix is to upgrade to release 9.2.0653 or later.

Risk and Exploitability

The CVSS base score of 5.7 indicates moderate severity. Because the EPSS score is not available and the vulnerability is not in the KEV catalog, the likelihood of exploitation is uncertain. The attack vector is inferred to be a local or user-supplied spell file, requiring the user to open a document that triggers spell suggestions; no external network exploitation is documented.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

vim

affected

Version	Status	Constraints
`< 9.2.0653`	affected	—

Configuration 1 [-]

cpe:2.3:a:vim:vim:*:*:*:*:*:*:*:*

No data.

Vendor Product Versions

Vim

Version	Status	Scheme	Platform
`[0,9.2.0653)`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Update Vim to 9.2.0653 or newer.
If an update is not immediately possible, disable spell suggestion features or remove untrusted spell files from the spell directory.
Verify that any custom .spl/.sug files come from trusted sources and delete or quarantine unknown files.
Consider running Vim with limited permissions or from a sandbox to mitigate impact.

Generated by OpenCVE AI on June 25, 2026 at 16:29 UTC.

Tracking

Advisories

Source	ID	Title
Ubuntu USN	USN-8500-1	Vim vulnerabilities

Metrics

Attack Vector Local

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction Active

Vulnerable System Confidentiality Impact High

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Local

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.124% probability within 30 days)

Exploitation none

Automatable no

Technical Impact total

References

Link	Providers
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
https://nvd.nist.gov/vuln/detail/CVE-2026-55693
https://www.cve.org/CVERecord?id=CVE-2026-55693

History

Jul 10, 2026 12:15 PM Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
References		https://nvd.nist.gov/vuln/detail/CVE-2026-55693 https://www.cve.org/CVERecord?id=CVE-2026-55693
Metrics	threat_severity `None`	cvssV3_1 `{'score': 7.3, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:H'}` threat_severity `Moderate`

Jun 26, 2026 2:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}`

Jun 25, 2026 10:30 PM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Vim Vim vim
Vendors & Products		Vim Vim vim

Jun 25, 2026 3:45 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
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.
Title		Vim: Out-of-bounds Write in Spell File Word Count
Weaknesses		CWE-787
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
Metrics		cvssV4_0 `{'score': 5.7, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U'}`