CVE-2026-55126: Microsoft SharePoint cross-site scripting vulnerability

CVE-2026-55126 · Severity: high · CVSS 7.3 · Published 2026-07-14

Microsoft SharePoint, a widely used collaboration and document management platform, is vulnerable to a security flaw that allows authenticated users to perform spoofing attacks. By tricking another user into interacting with a malicious link or page, an attacker could potentially steal sensitive information or perform actions on behalf of that user. This could lead to unauthorized access to corporate documents or the compromise of user accounts within the organization.

Technologies: Microsoft SharePoint Enterprise Server 2016, Microsoft SharePoint Server 2019, Microsoft SharePoint Server Subscription Edition. Vendors: Microsoft.

Quick answers

Is CVE-2026-55126 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-55126 being exploited in the wild.
How severe is CVE-2026-55126?
High severity, with a CVSS score of 7.3, published 14 July 2026.
Which products and versions are affected?
Microsoft SharePoint Enterprise Server 2016 < 16.0.5561.1001; Microsoft SharePoint Server 2019 < 16.0.10417.20175; Microsoft SharePoint Server Subscription Edition < 16.0.19725.20434.
Is there a fix for CVE-2026-55126?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-55126 attacked?
It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-55126?
Check whether you run Microsoft SharePoint Enterprise Server 2016, Microsoft SharePoint Server 2019 or Microsoft SharePoint Server Subscription Edition at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A cross-site scripting (XSS) vulnerability exists in Microsoft SharePoint due to improper neutralization of input during web page generation (CWE-79). An authenticated attacker with low privileges can exploit this vulnerability by sending a specially crafted request to a vulnerable SharePoint server. Successful exploitation requires a victim to interact with a malicious link or page (User Interaction: Required). This allows the attacker to execute arbitrary script in the context of the victim's browser, potentially leading to session hijacking, data theft, or unauthorized modifications. Microsoft has released security updates to address this issue across affected versions of SharePoint Server.

Affected products

  • Microsoft SharePoint Enterprise Server 2016 < 16.0.5561.1001
  • Microsoft SharePoint Server 2019 < 16.0.10417.20175
  • Microsoft SharePoint Server Subscription Edition < 16.0.19725.20434

Timeline

  • 2026-07-14: disclosed
  • 2026-07-14: advisory

References

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