CVE-2026-45484: Microsoft Office SharePoint privilege escalation via deserialization

CVE-2026-45484 · Severity: high · CVSS 8.8 · Published 2026-06-09

Microsoft SharePoint, a widely used platform for document management and team collaboration, contains a security flaw that could allow an authorized user to gain higher-level administrative permissions. By exploiting this vulnerability, an attacker with basic access could potentially take full control of the SharePoint environment, leading to the unauthorized access, modification, or deletion of sensitive corporate data. This poses a significant risk to organizational data integrity and confidentiality.

Technologies: Microsoft SharePoint. Vendors: Microsoft.

Quick answers

Is CVE-2026-45484 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-45484 being exploited in the wild.
How severe is CVE-2026-45484?
High severity, with a CVSS score of 8.8, published 9 June 2026.
Which products and versions are affected?
Microsoft Office SharePoint.
Is there a fix for CVE-2026-45484?
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-2026-45484 attacked?
It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-45484?
Check whether you run Microsoft SharePoint. 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 deserialization of untrusted data vulnerability (CWE-502) exists in Microsoft Office SharePoint. The flaw is triggered when the application improperly processes specially crafted serialized data sent over the network. An attacker must be authenticated with low-level privileges to exploit this issue. Successful exploitation allows the attacker to achieve elevation of privilege, potentially gaining full control over the affected SharePoint server (Confidentiality, Integrity, and Availability impact are all rated as High). Microsoft has released security updates to address this vulnerability; users should refer to the MSRC update guide for specific patch details.

Affected products

  • Microsoft Office SharePoint

Timeline

  • 2026-06-09: disclosed: Initial publication of CVE-2026-45484 by Microsoft.
  • 2026-06-09: advisory: NVD record published.

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.