# CVE-2026-64901: Microsoft Office SharePoint deserialization of untrusted data

Source: https://junglewise.ai/threats/cve-2026-64901-microsoft-office-sharepoint-deserialization-of-untrusted-data  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-11. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-64901 · Severity: high · CVSS 8.8 · Published 2026-08-11

Microsoft Office SharePoint contains a deserialization vulnerability that allows an authorized attacker to execute arbitrary code remotely over a network. Exploitation could lead to complete compromise of SharePoint servers and access to sensitive business documents and data stored within the platform.

Technologies: [Microsoft Office SharePoint](https://junglewise.ai/threats/technologies/office-sharepoint). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-64901 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-64901 being exploited in the wild.

**How severe is CVE-2026-64901?** High severity, with a CVSS score of 8.8, published 11 August 2026.

**Which products and versions are affected?** Microsoft Office SharePoint <UNKNOWN>.

**Is there a fix for CVE-2026-64901?** 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-2026-64901 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-64901?** Check whether you run Microsoft Office SharePoint 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

The vulnerability exists in the deserialization of untrusted data within Microsoft Office SharePoint. An authorized attacker with network access can craft malicious serialized objects that, when deserialized by the application, execute arbitrary code with the privileges of the SharePoint service. The attack requires authentication but can be executed over the network. Patches are available from Microsoft via their security update guide.

## Affected products

- Microsoft Office SharePoint <UNKNOWN>

## Timeline

- 2026-08-11: disclosed
- 2026-08-11: advisory

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64901](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64901)

## Related threats

- [Microsoft Office SharePoint privilege escalation via missing authorization](https://junglewise.ai/threats/cve-2026-88176-missing-authorization-in-microsoft-office-sharepoint-allows-an)
- [Microsoft Office SharePoint XSS privilege escalation](https://junglewise.ai/threats/cve-2026-80095-improper-neutralization-of-input-during-web-page-generation-cross)
- [Microsoft Office SharePoint server-side request forgery](https://junglewise.ai/threats/cve-2026-124210-server-side-request-forgery-ssrf-in-microsoft-office-sharepoint)
- [Microsoft Office SharePoint privilege escalation via incorrect authorization](https://junglewise.ai/threats/cve-2026-123391-incorrect-authorization-in-microsoft-office-sharepoint-allows-an)
- [Microsoft Office SharePoint deserialization of untrusted data](https://junglewise.ai/threats/cve-2026-123390-deserialization-of-untrusted-data-in-microsoft-office-sharepoint)