CVE-2021-3927

Crash or code execution via invalid cursor column

Published Nov 5, 2021 · Updated Aug 3, 2024

Heap-based buffer overflow in Vim before 8.2.3581 allows local users to crash or execute code by opening a crafted file. The gchar_cursor() logic in src/misc1.c can read past the end of a line when the cursor column is invalid, corrupting heap memory. Exploitation requires a victim to open the crafted file, so the practical impact is local and user-triggered rather than remotely reachable.

CVSS severity7.8
High
EPSS probability1.71%
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 8.2.3581 allows local users to crash or execute code by opening a crafted file. The gchar_cursor() logic in src/misc1.c can read past the end of a line when the cursor column is invalid, corrupting heap memory. Exploitation requires a victim to open the crafted file, so the practical impact is local and user-triggered rather than remotely reachable.

The record

CVE
CVE-2021-3927
Published
Nov 5, 2021
Updated
Aug 3, 2024
Vendor
Vim
Product
Vim
Classifications
CWE-122, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 5, 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 <8.2.3581

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Vim · Vimversion=unspecified <8.2.3581

Published CVSS scores

7.3huntr.devCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:H
7.8NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NVDAV:N/AC:M/Au:N/C:P/I:P/A:P

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 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
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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