CVE-2026-58639Network attack vector

Spoofing via authenticated server-side request forgery

Published Aug 11, 2026 · Updated Aug 25, 2026

Server-side request forgery in Microsoft SharePoint allows remote authenticated users to spoof network requests over the network. The public record does not identify the vulnerable SharePoint endpoint or outbound request sink; Microsoft has disclosed only that attacker-controlled input can make the server issue forged requests. Reachability requires valid low-privileged SharePoint access on Enterprise Server 2016 before 16.0.5565.1001, Server 2019 before 16.0.10417.20198, or Subscription Edition before 16.0.19725.20522, with published impact limited to confidentiality rather than code execution or service interruption.

CVSS severity6.5
Medium
EPSS probability0.83%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Server-side request forgery in Microsoft SharePoint allows remote authenticated users to spoof network requests over the network. The public record does not identify the vulnerable SharePoint endpoint or outbound request sink; Microsoft has disclosed only that attacker-controlled input can make the server issue forged requests. Reachability requires valid low-privileged SharePoint access on Enterprise Server 2016 before 16.0.5565.1001, Server 2019 before 16.0.10417.20198, or Subscription Edition before 16.0.19725.20522, with published impact limited to confidentiality rather than code execution or service interruption.

The record

CVE
CVE-2026-58639
Published
Aug 11, 2026
Updated
Aug 25, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-918
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.5Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/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-918Server-Side Request Forgery (SSRF)

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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