CVE-2025-49706Known exploitationPublic exploitNetwork attack vector

Unauthenticated ToolPane access via forged Referer header

Published Jul 8, 2025 · Updated Aug 4, 2026

Improper authentication in Microsoft SharePoint Server 2016, 2019, and Subscription Edition allows remote attackers to bypass access controls. The ToolPane endpoint trusts a crafted Referer header pointing to SignOut.aspx and exposes a protected API without validating a session. No credentials or user interaction are required; the flaw grants unauthorized ToolPane access and has been chained with a separate deserialization flaw for code execution.

CVSS severity6.5
Medium
EPSS probability99.06%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in Microsoft SharePoint Server 2016, 2019, and Subscription Edition allows remote attackers to bypass access controls. The ToolPane endpoint trusts a crafted Referer header pointing to SignOut.aspx and exposes a protected API without validating a session. No credentials or user interaction are required; the flaw grants unauthorized ToolPane access and has been chained with a separate deserialization flaw for code execution.

The record

CVE
CVE-2025-49706
Published
Jul 8, 2025
Updated
Aug 4, 2026
Vendor
Microsoft
Product
Microsoft SharePoint Enterprise Server 2016
Classifications
CWE-287, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 7, 2025Exploitation reportedMicrosoft-observed ToolShell exploitation
  2. Jul 8, 2025CVE publishedPublication date reported by the CVE source.
  3. Jul 18, 2025Exploitation reportedWarlock ransomware deployment by Storm-2603
  4. Aug 4, 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 <16.0.5508.1000

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft SharePoint Enterprise Server 2016version=16.0.0 <16.0.5508.1000
Microsoft · Microsoft SharePoint Server 2019version=16.0.0 <16.0.10417.20027
Microsoft · Microsoft SharePoint Server Subscription Editionversion=16.0.0 <16.0.18526.20424

Published CVSS scores

6.5Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
6.5Trend Micro Zero Day InitiativeCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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.

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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 exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-287Improper Authentication
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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