CVE-2025-49706: Microsoft SharePoint Improper Authentication Vulnerability

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Yes, if you run Microsoft SharePoint. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2025-07-22, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2025-07-23; treat that as the outer limit, not the target. CISA also lists it as known to be used in ransomware campaigns.
• EPSS 99.1%, percentile 99.9: FIRST’s model estimates a 99.1% chance of exploitation activity in the next 30 days, higher than 99.9% of all scored CVEs (very high). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Editorial verdict: Check exposure. ToolShell: SharePoint On-Prem Unauthenticated RCE Chain — Fixes shipped in July 2025, but ToolShell stole ASP.NET machine keys that survive patching, so any on-prem SharePoint that was internet-facing then needs proof that keys were rotated and no backdoor remains.

What it is

Improper authentication in Microsoft Office SharePoint allows an unauthorized attacker to perform spoofing over a network.

CISA’s summary

Microsoft SharePoint contains an improper authentication vulnerability that allows an authorized attacker to perform spoofing over a network. Successfully exploitation could allow an attacker to view sensitive information and make some changes to disclosed information. This vulnerability could be chained with CVE-2025-49704. CVE-2025-53771 is a patch bypass for CVE-2025-49706, and the updates for CVE-2025-53771 include more robust protection than those for CVE-2025-49706.

Weakness type: CWE-287.

Product: Microsoft SharePoint · Assigned by: microsoft · Published: 2025-07-08

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: added 2025-07-22; federal due date 2025-07-23. Known ransomware use: Known.
• CISA required action: Disconnect public-facing versions of SharePoint Server that have reached their end-of-life (EOL) or end-of-service (EOS) to include SharePoint Server 2013 and earlier versions. For supported versions, please follow the mitigations according to CISA (URL listed below in Notes) and vendor instructions (URL listed below in Notes). Adhere to the applicable BOD 22-01 guidance for cloud services or discontinue use of the product if mitigations are not available.
• CISA SSVC assessment: exploitation active, automatable no, technical impact partial.
• FIRST EPSS (model of 2026-10-21): 99.09% probability of exploitation activity in the next 30 days; percentile 99.9.

Timeline

• 2025-07-08 — CVE record published by microsoft
• 2025-07-19 — erroneo.us brief: ToolShell: SharePoint On-Prem Unauthenticated RCE Chain
• 2025-07-22 — Added to CISA’s Known Exploited Vulnerabilities catalog
• 2025-07-23 — CISA remediation deadline for US federal agencies
• 2026-08-04 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

1. Microsoft SharePoint Server Spoofing Vulnerability msrc.microsoft.com
2. microsoft.com microsoft.com

Vulnerability records

1. CVE.org record CVE-2025-49706 cve.org
2. NVD entry CVE-2025-49706 nvd.nist.gov

Government

1. CISA Known Exploited Vulnerabilities catalog entry cisa.gov
2. Listed in CISA KEV notes (cisa.gov) cisa.gov

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