CVE-2021-3973

Editor crash via unchecked empty filename selection

Published Nov 19, 2021 · Updated Aug 3, 2024

Heap-based buffer overflow in Vim before 8.2.3611 allows local users to crash the editor by invoking CTRL-W f on an empty selection. get_visual_text treats a NUL at the visual cursor as a one-byte selection, and the file-search path continues with the invalid length instead of rejecting it. Triggering the fault requires an interactive Vim session and the affected visual-block command path; the demonstrated consequence is an editor crash.

CVSS severity7.8
High
EPSS probability1.79%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in Vim before 8.2.3611 allows local users to crash the editor by invoking CTRL-W f on an empty selection. get_visual_text treats a NUL at the visual cursor as a one-byte selection, and the file-search path continues with the invalid length instead of rejecting it. Triggering the fault requires an interactive Vim session and the affected visual-block command path; the demonstrated consequence is an editor crash.

The record

CVE
CVE-2021-3973
Published
Nov 19, 2021
Updated
Aug 3, 2024
Vendor
Vim
Product
Vim
Classifications
CWE-122, CWE-787, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 19, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <8.2.3611

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Vim · Vimversion=unspecified <8.2.3611

Published CVSS scores

7.3huntr.devCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:H
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
9.3NIST NVDAV:N/AC:M/Au:N/C:C/I:C/A:C

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
CWE-787Out-of-bounds Write
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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