CVE-2021-43209

Code execution via 3MF parser use-after-free

Published Nov 10, 2021 · Updated Aug 19, 2026

Use-after-free in Microsoft 3D Viewer before 7.2107.7012.0 allows remote attackers to execute code through a crafted 3MF file. The 3MF parser performs operations on an object without first validating that the object still exists, creating a use-after-free condition. Exploitation requires the target to open the file or visit a malicious page, and code runs in the current process at low integrity.

CVSS severity7.8
High
EPSS probability6.77%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Microsoft 3D Viewer before 7.2107.7012.0 allows remote attackers to execute code through a crafted 3MF file. The 3MF parser performs operations on an object without first validating that the object still exists, creating a use-after-free condition. Exploitation requires the target to open the file or visit a malicious page, and code runs in the current process at low integrity.

The record

CVE
CVE-2021-43209
Published
Nov 10, 2021
Updated
Aug 19, 2026
Vendor
Microsoft
Product
3D Viewer
Classifications
T1204.002, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 10, 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=7.0.0 <7.2107.7012.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Microsoft · 3D Viewerversion=7.0.0 <7.2107.7012.0

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
7.8Microsoft CorporationCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8Microsoft CorporationCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
6.8NIST NVDAV: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

T1204.002User Execution: Malicious File
T1203Exploitation for Client Execution

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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