CVE-2026-55892

Vim: Out-of-bounds Write in Spell File Prefix Dump

Published Jun 25, 2026 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed

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.

Analysis

Technical impact

The vulnerability resides in the dump_prefixes() function of Vim’s spell file handling. A counter that measures traversal depth is not bounded against the fixed-size stack arrays. A maliciously crafted .spl file can force the function to descend arbitrarily deep, causing a stack out‑of‑bounds write and corrupting the call frame. The result is a crash of Vim; the presence of an overflow also raises the possibility of executing arbitrary code if the stack corruption can be controlled.

Affected Systems

Vendor: Vim. Product: vim. Versions: any release prior to 9.2.0662, where the bug is present.

Risk and Exploitability

With a CVSS score of 5.5 the vulnerability is of moderate severity. No EPSS value is reported and it is not listed in CISA’s KEV catalog. The exploit requires the attacker to supply a crafted .spl file that Vim loads during a prefix dump, which is typically a local or file‑based attack. Because the overflow can corrupt the stack, the risk of privilege escalation or remote code execution exists, but exploitation is not guaranteed without additional conditions.

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
`< 9.2.0662`	affected	—

Configuration 1 [-]

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

No data.

Vendor Product Versions

Vim

Version	Status	Scheme	Platform
`[0,9.2.0662)`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Upgrade Vim to 9.2.0662 or later where the issue is fixed.
If an upgrade is not immediately possible, refrain from loading or dumping word lists from untrusted spell files.
Monitor Vim releases for additional patches and apply them as soon as they become available.

Generated by OpenCVE AI on June 25, 2026 at 16:30 UTC.

Tracking

Advisories

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

Metrics

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

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% (0.120% probability within 30 days)

Exploitation none

Automatable no

Technical Impact partial

References

Link	Providers
https://github.com/vim/vim/commit/8325b193bba5f01e7a7d8241f
https://github.com/vim/vim/releases/tag/v9.2.0662
https://github.com/vim/vim/security/advisories/GHSA-qm9w-fmpj-879h
https://nvd.nist.gov/vuln/detail/CVE-2026-55892
https://www.cve.org/CVERecord?id=CVE-2026-55892

History

Jun 30, 2026 12:45 AM Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
References		https://nvd.nist.gov/vuln/detail/CVE-2026-55892 https://www.cve.org/CVERecord?id=CVE-2026-55892
Metrics	threat_severity `None`	threat_severity `Moderate`

Jun 26, 2026 7:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, '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 9.2.0662, 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.
Title		Vim: Out-of-bounds Write in Spell File Prefix Dump
Weaknesses		CWE-787
References		https://github.com/vim/vim/commit/8325b193bba5f01e7a7d8241f https://github.com/vim/vim/releases/tag/v9.2.0662 https://github.com/vim/vim/security/advisories/GHSA-qm9w-fmpj-879h
Metrics		cvssV3_1 `{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H'}`