CVE-2026-56157Network attack vector

Authenticated content spoofing via undisclosed access control

Published Jul 14, 2026 · Updated Jul 14, 2026

Improper access control in Microsoft SharePoint Server allows remote authenticated users to spoof content over a network. Microsoft has not published the affected request path or the access-control operation that mishandles authenticated input. A low-privileged account and network access are required; exploitation can expose limited information and alter trusted content, but cannot interrupt service.

CVSS severity5.4
Medium
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in Microsoft SharePoint Server allows remote authenticated users to spoof content over a network. Microsoft has not published the affected request path or the access-control operation that mishandles authenticated input. A low-privileged account and network access are required; exploitation can expose limited information and alter trusted content, but cannot interrupt service.

The record

CVE
CVE-2026-56157
Published
Jul 14, 2026
Updated
Jul 14, 2026
Vendor
Microsoft
Product
Microsoft SharePoint Enterprise Server 2016
Classifications
CWE-284
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 14, 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 <16.0.5561.1001

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Microsoft · Microsoft SharePoint Enterprise Server 2016version=16.0.0 <16.0.5561.1001
Microsoft · Microsoft SharePoint Server 2019version=16.0.0 <16.0.10417.20175
Microsoft · Microsoft SharePoint Server Subscription Editionversion=16.0.0 <16.0.19725.20434

Published CVSS scores

5.4MicrosoftCVSS:3.1/AV:N/AC:L/PR:L/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control

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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