Is CVE-2026-55135 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-55135 being exploited in the wild.

How severe is CVE-2026-55135?

Medium severity, with a CVSS score of 4.6, 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-2026-55135?

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-2026-55135 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-55135?

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.

CVE-2026-55135: Microsoft Office SharePoint cross-site scripting

Q: Is there a fix for CVE-2026-55135?

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.

Q: How is CVE-2026-55135 attacked?

It is attacked over the network, in a network appliance.

Q: Am I affected by CVE-2026-55135?

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.

CVE-2026-55135 · Severity: medium · CVSS 4.6 · Published 2026-07-14

Microsoft SharePoint, a widely used collaboration and document management platform, is affected by a security vulnerability that could allow an attacker to perform spoofing attacks. An authorized user could exploit this flaw to execute malicious scripts in another user's browser session, potentially leading to unauthorized actions or the theft of sensitive information. This could compromise the integrity of internal communications and data handled within the SharePoint environment.

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

Quick answers

Is CVE-2026-55135 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-55135 being exploited in the wild.
How severe is CVE-2026-55135?: Medium severity, with a CVSS score of 4.6, 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-2026-55135?: 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-2026-55135 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-55135?: 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 (CWE-79) exists in Microsoft SharePoint due to improper neutralization of input during web page generation. An authenticated attacker with low privileges can exploit this over the network by convincing a victim to interact with a specially crafted link or page. Successful exploitation allows the attacker to execute arbitrary script in the context of the victim's browser, enabling spoofing or unauthorized data access. The vulnerability affects SharePoint Enterprise Server 2016, SharePoint Server 2019, and SharePoint Server Subscription Edition; patches are available through Microsoft's standard update channels.

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

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55135

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