Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2025-53770

Microsoft SharePoint Server Remote Code Execution Vulnerability

Microsoft SharePoint Enterprise Server 2016 · affected before 16.0.5513.1001

Watch CVE-2025-53770 Browse KEV feed
Severity
CVSS 9.8 · Critical
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
100.0%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2025-53770 is an unauthenticated Microsoft SharePoint Server Remote Code Execution Vulnerability. Deserialization of untrusted data in on-premises Microsoft SharePoint Server allows an unauthorized attacker to...

Is it exploited?

Yes. Previdian tracks this CVE as a known exploited vulnerability. Confidence is confirmed. Listed in CISA KEV. Also confirmed by third-party sources.

Who is affected?

Microsoft SharePoint Enterprise Server 2016 affected before 16.0.5513.1001.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Microsoft SharePoint Server Remote Code Execution Vulnerability

Deserialization of untrusted data in on-premises Microsoft SharePoint Server allows an unauthorized attacker to execute code over a network. Microsoft is aware that an exploit for CVE-2025-53770 exists in the wild.

Microsoft is preparing and fully testing a comprehensive update to address this vulnerability. In the meantime, please make sure that the mitigation provided in this CVE documentation is in place so that you are protected from exploitation.

Microsoft Affected
Microsoft SharePoint Enterprise Server 2016
Before 16.0.5513.1001
Microsoft Affected
Microsoft SharePoint Server 2019
Before 16.0.10417.20037
Microsoft Affected
Microsoft SharePoint Server Subscription Edition
Before 16.0.18526.20508
View vendor advisory (opens in new tab)
Published
20 Jul 2025
Exploitation Reported
01 Jun 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

cisa nuclei_scanner microsoft malware metasploit_scanner

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CVE

Recorded 01 Jun 2026

A trusted third party reported exploitation.

Used in malware

CVE

Recorded 02 Jun 2026

Malware families have been linked to exploitation of this CVE.

Proof of concept available

Nuclei Templates

Recorded 12 Jun 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
CVE First 2026-06-01 10:37 UTC
The Shadowserver 2026-06-02 00:00 UTC
CISA 2026-06-02 14:06 UTC
Daily CyberSecurity 2026-06-11 01:20 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
0
0
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2025/CVE-2025-53770.yaml 01 Jun 2026
Metasploit https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/windows/http/sharepoint_toolpane_rce.rb 08 Jul 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

9.8 Critical

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:W/RC:C

EPSS

100.0%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Deserialization of Untrusted Data CWE-502

Recent mention · BleepingComputer

How to secure RMM software: 8 controls MSPs should test

RMM platforms give MSPs privileged access across customer environments, making their security controls critical to limiting risk. Acronis outlines eight controls MSPs should test when evaluating RMM software, from patching and privileged access to recovery and tenant...

Read full advisory

All Mentions

Recent mention · BleepingComputer

How to secure RMM software: 8 controls MSPs should test

BleepingComputer · 06 Oct 2026

RMM platforms give MSPs privileged access across customer environments, making their security controls critical to limiting risk. Acronis outlines eight controls MSPs should test when evaluating RMM software, from patching and privileged access to recovery and tenant isolation. [...]

Recent mention · Daily CyberSecurity

Millions at Risk: 9.8 CVSS Remote Code Execution in HTTP.sys

Daily CyberSecurity · 12 Jun 2026

The tech world faces a severe threat today. Millions of users are currently at risk due to a The post Millions at Risk: 9.8 CVSS Remote Code Execution in HTTP.sys appeared first on Daily CyberSecurity. Related posts: FiberGateway Router Hacked: Portugal’s 1.6M Homes at Risk Critical HIKVISION applyCT Flaw (CVE-2025-34067, CVSS 10.0): Unauthenticated RCE Via Fastjson SharePoint Server Under Active Zero-Day Attack (CVE-2025-53770, CVSS 9.8), No Patch Yet!

Recent mention · Daily CyberSecurity

Splunk Enterprise Vulnerabilities: Patch CVSS 9.8 Flaws

Daily CyberSecurity · 11 Jun 2026

Security administrators must urgently patch multiple critical Splunk Enterprise vulnerabilities recently disclosed by the vendor. These highly severe The post Splunk Enterprise Vulnerabilities: Patch CVSS 9.8 Flaws appeared first on Daily CyberSecurity. Related posts: High-Privilege Havoc: Splunk Patches RCE Flaw Lurking in File Previews AI Spam Threatens cURL’s Bug Bounty Program: Developer Considers Shutting It Down SharePoint Server Under Active Zero-Day Attack (CVE-2025-53770, CVSS 9.8), No Patch Yet!

Recent mention · Daily CyberSecurity

Spring Data Vulnerabilities: Patch Five Critical Flaws Now

Daily CyberSecurity · 11 Jun 2026

Cybersecurity experts recently disclosed five severe Spring Data vulnerabilities. Consequently, software developers must act quickly to secure their The post Spring Data Vulnerabilities: Patch Five Critical Flaws Now appeared first on Daily CyberSecurity. Related posts: AI Spam Threatens cURL’s Bug Bounty Program: Developer Considers Shutting It Down SharePoint Server Under Active Zero-Day Attack (CVE-2025-53770, CVSS 9.8), No Patch Yet! CISA Alert: Actively Exploited Zero-Days in CrushFTP, Chrome, and SysAid Added to KEV Catalog

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

Microsoft SharePoint Server - Remote Code Execution (ToolShell)

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation

  1. 14:21 UTC

    Public PoC available

    Public proof-of-concept code published

  2. 01:20 UTC

    KEV confirmed by Daily CyberSecurity

    Exploitation attested by an external source

  3. 14:07 UTC

    First public exploitation report

    Exploit observed in malware

  4. 14:06 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  5. 00:00 UTC

    KEV confirmed by The Shadowserver

    Exploitation attested by an external source

  6. 15:34 UTC

    Nuclei template available

    Scanner coverage available

  7. 10:37 UTC

    Added to Previdian KEV Feed

    High-confidence, third-party attested exploitation

  8. 01:06 UTC

    CVE published

    Vulnerability disclosed publicly

  9. 13:25 UTC

    CVE ID reserved

    Identifier reserved by the CNA

  10. 00:00 UTC

    Metasploit module available

    Exploit module available

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

Start 14-day Pro trial Read API docs
  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2025-53770

Sample API response 
{
  "cve_id": "CVE-2025-53770",
  "confidence": "Confirmed",
  "cvss_score": 9.8,
  "cvss_estimated": false,
  "epss_score": 0.99999,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}