CVE-2025-21393Network attack vector

Authenticated content spoofing via undisclosed cross-site scripting

Published Jan 14, 2025 · Updated Jun 9, 2026

Cross-site scripting in affected Microsoft SharePoint Server editions allows remote authenticated users to spoof content through crafted input. Microsoft has not published the affected endpoint or the operation that fails to neutralize the input before placing it in a generated page. Exploitation requires low-privileged authenticated access and user interaction, and can expose data or alter displayed content without interrupting service.

CVSS severity6.3
Medium
EPSS probability1.08%
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 affected Microsoft SharePoint Server editions allows remote authenticated users to spoof content through crafted input. Microsoft has not published the affected endpoint or the operation that fails to neutralize the input before placing it in a generated page. Exploitation requires low-privileged authenticated access and user interaction, and can expose data or alter displayed content without interrupting service.

The record

CVE
CVE-2025-21393
Published
Jan 14, 2025
Updated
Jun 9, 2026
Vendor
Microsoft
Product
Microsoft SharePoint Enterprise Server 2016
Classifications
CWE-79
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 14, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 9, 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 <16.0.5483.1001

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Microsoft · Microsoft SharePoint Enterprise Server 2016version=16.0.0 <16.0.5483.1001
Microsoft · Microsoft SharePoint Server 2019version=16.0.0 <16.0.10416.20041
Microsoft · Microsoft SharePoint Server Subscription Editionversion=16.0.0 <16.0.17928.20356

Published CVSS scores

6.3Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/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')

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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