CVE-2021-28464

User-assisted code execution

Published Apr 13, 2021 · Updated May 28, 2026

Remote code execution in Microsoft VP9 Video Extensions allows context-dependent attackers to execute code via unspecified vectors. Microsoft has not published the affected decoder locus or the operation it performs incorrectly on untrusted input. Reachability requires user interaction but no prior privileges; successful exploitation runs code in the affected media-processing context.

CVSS severity7.8
High
EPSS probability2.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Remote code execution in Microsoft VP9 Video Extensions allows context-dependent attackers to execute code via unspecified vectors. Microsoft has not published the affected decoder locus or the operation it performs incorrectly on untrusted input. Reachability requires user interaction but no prior privileges; successful exploitation runs code in the affected media-processing context.

The record

CVE
CVE-2021-28464
Published
Apr 13, 2021
Updated
May 28, 2026
Vendor
Microsoft
Product
VP9 Video Extensions
Classifications
Unavailable
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 13, 2021CVE publishedPublication date reported by the CVE source.
  2. May 28, 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=N/A

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Microsoft · VP9 Video Extensionsversion=N/A

Published CVSS scores

7.8Microsoft CorporationCVSS:3.1/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 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

No sourced classifications are available.

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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