CVE-2020-1101Network attack vector

Authenticated script execution via unsanitized web request

Published May 21, 2020 · Updated Aug 19, 2026

Cross-site scripting in Microsoft SharePoint Server allows remote authenticated users to run script in a victim's browser via a crafted request. The web-request rendering path embeds attacker-controlled request data into generated page content without proper sanitization; Microsoft has not identified the endpoint or parameter. A victim must interact with the resulting content while signed in, after which the script can read unauthorized content or act as that user, including changing permissions or deleting content.

CVSS severity5.4
Medium
EPSS probability1.71%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Microsoft SharePoint Server allows remote authenticated users to run script in a victim's browser via a crafted request. The web-request rendering path embeds attacker-controlled request data into generated page content without proper sanitization; Microsoft has not identified the endpoint or parameter. A victim must interact with the resulting content while signed in, after which the script can read unauthorized content or act as that user, including changing permissions or deleting content.

The record

CVE
CVE-2020-1101
Published
May 21, 2020
Updated
Aug 19, 2026
Vendor
Microsoft
Product
Microsoft SharePoint Foundation 2013
Classifications
CWE-79, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 21, 2020CVE 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=15.0.0 <publication

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Microsoft · Microsoft SharePoint Foundation 2013version=15.0.0 <publication
Microsoft · Microsoft SharePoint Enterprise Server 2016version=16.0.0 <publication
Microsoft · Microsoft SharePoint Server 2019version=16.0.0 <publication

Published CVSS scores

5.4CISA-ADPCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1190Exploit Public-Facing Application

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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