Quick answers
- Is CVE-2026-66808 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-66808 being exploited in the wild.
- How severe is CVE-2026-66808?
- 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-2026-66808?
- 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-2026-66808 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-66808?
- 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 stems from unsafe deserialization of untrusted data in Microsoft Office SharePoint. An authenticated attacker with network access can send specially crafted serialized objects that, when deserialized by the SharePoint application, trigger remote code execution. This is a pre-authentication attack requiring valid credentials but no additional user interaction. Successful exploitation grants the attacker the ability to execute arbitrary commands with the privileges of the SharePoint service account.
Affected products
- Microsoft Office SharePoint <UNKNOWN>
Timeline
- 2026-08-11: disclosed