CVE-2026-20945Network attack vectorHinoki check available

Authenticated content spoofing via undisclosed cross-site scripting

Published Apr 14, 2026 · Updated Apr 14, 2026

Cross-site scripting in Microsoft SharePoint Server allows remote authenticated users to spoof web content over a network. Microsoft identifies improper neutralization during web-page generation but has not disclosed the affected request, input field, or rendering routine that places attacker-controlled input into output. Exploitation requires SharePoint authorization and victim interaction; the reported consequence is deceptive page content rather than a service interruption.

CVSS severity4.6
Medium
EPSS probability19.07%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Cross-site scripting in Microsoft SharePoint Server allows remote authenticated users to spoof web content over a network. Microsoft identifies improper neutralization during web-page generation but has not disclosed the affected request, input field, or rendering routine that places attacker-controlled input into output. Exploitation requires SharePoint authorization and victim interaction; the reported consequence is deceptive page content rather than a service interruption.

The record

CVE
CVE-2026-20945
Published
Apr 14, 2026
Updated
Apr 14, 2026
Vendor
Microsoft
Product
Microsoft SharePoint Enterprise Server 2016
Classifications
CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 14, 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=16.0.0 <16.0.5548.1003

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Microsoft · Microsoft SharePoint Enterprise Server 2016version=16.0.0 <16.0.5548.1003
Microsoft · Microsoft SharePoint Server 2019version=16.0.0 <16.0.10417.20114
Microsoft · Microsoft SharePoint Server Subscription Editionversion=16.0.0 <16.0.19725.20210

Published CVSS scores

4.6Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
5.4NIST NVDCVSS: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 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

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