CVE-2021-26414Public exploitNetwork attack vector

Integrity bypass via weak DCOM activation authentication

Published Jun 8, 2021 · Updated Aug 3, 2024

Security feature bypass in Microsoft Windows DCOM allows remote authenticated users to alter activation traffic through network requests. DCOM servers accept activation requests below RPC_C_AUTHN_LEVEL_PKT_INTEGRITY, leaving the request without the packet-integrity protection later enforced by Microsoft. Exploitation requires low privileges and user interaction and affects integrity without reported data disclosure or service interruption.

CVSS severity4.8
Medium
EPSS probability49.84%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Security feature bypass in Microsoft Windows DCOM allows remote authenticated users to alter activation traffic through network requests. DCOM servers accept activation requests below RPC_C_AUTHN_LEVEL_PKT_INTEGRITY, leaving the request without the packet-integrity protection later enforced by Microsoft. Exploitation requires low privileges and user interaction and affects integrity without reported data disclosure or service interruption.

The record

CVE
CVE-2021-26414
Published
Jun 8, 2021
Updated
Aug 3, 2024
Vendor
Microsoft
Product
Windows 10 Version 1507
Classifications
T1557
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 8, 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

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=10.0.0 <10.0.10240.19802

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Microsoft · Windows 10 Version 1507version=10.0.0 <10.0.10240.19802
Microsoft · Windows Server 2019version=10.0.0 <10.0.17763.4131
Microsoft · Windows 7version=6.1.0 <6.1.7601.25984
Microsoft · Windows 10 Version 21H1version=10.0.0 <10.0.19043.1766
Microsoft · Windows 10 Version 1909version=10.0.0 <10.0.18363.2344
Microsoft · Windows 8.1version=6.3.0 <6.3.9600.20402
Microsoft · Windows Server 2016 (Server Core installation)version=10.0.0 <10.0.14393.5786
Microsoft · Windows 11 version 21H2version=10.0.0 <10.0.22000.1696
Microsoft · Windows Server 2012 (Server Core installation)version=6.2.0 <6.2.9200.24168
Microsoft · Windows Server 2012version=6.2.0 <6.2.9200.24168
Microsoft · Windows 10 Version 21H2version=10.0.0 <10.0.19044.2728
Microsoft · Windows Server 2016version=10.0.0 <10.0.14393.5786
Microsoft · Windows Server 2008 R2 Service Pack 1version=6.1.0 <6.1.7601.26415
Microsoft · Windows 10 Version 20H2version=10.0.0 <10.0.19042.2728
Microsoft · Windows Server 2008 R2 Service Pack 1 (Server Core installation)version=6.0.0 <6.1.7601.26415
Microsoft · Windows Server 2012 R2 (Server Core installation)version=6.3.0 <6.3.9600.20865
Microsoft · Windows Server 2019 (Server Core installation)version=10.0.0 <10.0.17763.4131
Microsoft · Windows 7 Service Pack 1version=6.1.0 <6.1.7601.25984
Microsoft · Windows 10 Version 1607version=10.0.0 <10.0.14393.5786
Microsoft · Windows Server 2008 Service Pack 2version=6.0.0 <6.0.6003.21966
Microsoft · Windows Server 2022version=10.0.0 <10.0.20348.1607
Microsoft · Windows 10 Version 1809version=10.0.0 <10.0.17763.4131
Microsoft · Windows Server 2012 R2version=6.3.0 <6.3.9600.20865
Microsoft · Windows Server 2008 Service Pack 2 (Server Core installation)version=6.0.0 <6.0.6003.21966

Published CVSS scores

4.8MicrosoftCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:N

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)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1557Adversary-in-the-Middle

Public exploit references

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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