CVE-2021-42297

SYSTEM code execution via symbolic-link folder deletion

Published Nov 24, 2021 · Updated Aug 19, 2026

Link-following in Microsoft Windows Update Assistant allows local users to elevate privileges through a crafted symbolic link. Windows Update Assistant follows an attacker-created symbolic link while deleting a folder, redirecting the privileged deletion to an attacker-chosen location. Exploitation requires local low-privileged access and user interaction, after which arbitrary code runs as SYSTEM.

CVSS severity5.0
Medium
EPSS probability1.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Link-following in Microsoft Windows Update Assistant allows local users to elevate privileges through a crafted symbolic link. Windows Update Assistant follows an attacker-created symbolic link while deleting a folder, redirecting the privileged deletion to an attacker-chosen location. Exploitation requires local low-privileged access and user interaction, after which arbitrary code runs as SYSTEM.

The record

CVE
CVE-2021-42297
Published
Nov 24, 2021
Updated
Aug 19, 2026
Vendor
Microsoft
Product
Windows Update Assistant
Classifications
CWE-59, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 24, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 19, 2026Record 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=10.0.0 <publication

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Microsoft · Windows Update Assistantversion=10.0.0 <publication

Published CVSS scores

5.0Microsoft CorporationCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
6.9NIST NVDAV:L/AC:M/Au:N/C:C/I:C/A:C
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.7Zero Day InitiativeCVSS:3.1/AV:L/AC:H/PR:L/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-59Improper Link Resolution Before File Access ('Link Following')
T1068Exploitation for Privilege Escalation

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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