CVE-2023-33159Network attack vector

User-assisted script execution via undisclosed input handling

Published Jul 11, 2023 · Updated Feb 28, 2025

Cross-site scripting in Microsoft SharePoint Server allows remote attackers to execute script in a user's browser via crafted content. Microsoft has not published the affected component, input field, or sanitization operation, so the precise code-level mechanism is undisclosed. Exploitation requires user interaction; the resulting script executes in the affected user's SharePoint browser context.

CVSS severity8.8
High
EPSS probability1.30%
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 attackers to execute script in a user's browser via crafted content. Microsoft has not published the affected component, input field, or sanitization operation, so the precise code-level mechanism is undisclosed. Exploitation requires user interaction; the resulting script executes in the affected user's SharePoint browser context.

The record

CVE
CVE-2023-33159
Published
Jul 11, 2023
Updated
Feb 28, 2025
Vendor
Microsoft
Product
Microsoft SharePoint Enterprise Server 2016
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 11, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 28, 2025Record 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 <16.0.5404.1000

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft SharePoint Enterprise Server 2016version=16.0.0 <16.0.5404.1000
Microsoft · Microsoft SharePoint Server 2019version=16.0.0 <16.0.10400.20008
Microsoft · Microsoft SharePoint Server Subscription Editionversion=16.0.0 <16.0.16130.20642

Published CVSS scores

8.8Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:R/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
Privilegesunauthenticated
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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