CVE-2021-43876Network attack vector

Authenticated privilege escalation via undisclosed mechanism

Published Dec 29, 2021 · Updated Aug 4, 2024

Privilege escalation in Microsoft SharePoint Server 2013, 2016, and 2019 allows remote authenticated users to gain elevated privileges. Microsoft has not published the affected component or the operation that mishandles attacker-controlled input. A low-privileged account and network access are required, and successful exploitation grants control beyond the account's assigned rights.

CVSS severity8.8
High
EPSS probability1.92%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Privilege escalation in Microsoft SharePoint Server 2013, 2016, and 2019 allows remote authenticated users to gain elevated privileges. Microsoft has not published the affected component or the operation that mishandles attacker-controlled input. A low-privileged account and network access are required, and successful exploitation grants control beyond the account's assigned rights.

The record

CVE
CVE-2021-43876
Published
Dec 29, 2021
Updated
Aug 4, 2024
Vendor
Microsoft
Product
Microsoft SharePoint Enterprise Server 2016
Classifications
T1068
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 29, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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=16.0.0 <16.0.5254.1000

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Microsoft · Microsoft SharePoint Enterprise Server 2016version=16.0.0 <16.0.5254.1000
Microsoft · Microsoft SharePoint Enterprise Server 2013version=15.0.0 <15.0.5407.1000
Microsoft · Microsoft SharePoint Server 2019version=16.0.0 <16.0.10381.20001

Published CVSS scores

6.0NIST NVDAV:N/AC:M/Au:S/C:P/I:P/A:P
8.8Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/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)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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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