CVE-2021-3872

Process crash via overlong buffer name

Published Oct 19, 2021 · Updated Nov 3, 2025

Heap-based buffer overflow in Vim before 8.2.3487 allows attackers to corrupt memory by opening a buffer with a very long name. The win_redr_status() function appends status markers after the buffer name without bounding each copy to the remaining MAXPATHL space. A user must open the crafted name and trigger status-line redraw; the resulting out-of-bounds write can crash the Vim process.

CVSS severity7.8
High
EPSS probability1.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Heap-based buffer overflow in Vim before 8.2.3487 allows attackers to corrupt memory by opening a buffer with a very long name. The win_redr_status() function appends status markers after the buffer name without bounding each copy to the remaining MAXPATHL space. A user must open the crafted name and trigger status-line redraw; the resulting out-of-bounds write can crash the Vim process.

The record

CVE
CVE-2021-3872
Published
Oct 19, 2021
Updated
Nov 3, 2025
Vendor
Vim
Product
Vim
Classifications
CWE-787, CWE-122
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 19, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=unspecified <8.2.3487

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Vim · Vimversion=unspecified <8.2.3487

Published CVSS scores

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

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-787Out-of-bounds Write
CWE-122Heap-based Buffer Overflow

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo