26 May 2026
Reference: CVE-2026-45659
1. What is being reported?
The issue involves a weakness in how SharePoint handles certain data, allowing someone with access to the system to run malicious code over the network. This means an attacker could potentially take control of the SharePoint server and access sensitive information or disrupt services.
2. What this means in plain English
For small organisations using SharePoint, this vulnerability could lead to serious problems like data breaches or downtime if exploited. Even authorised users with limited access might be able to cause harm, so it’s important to address this quickly to keep your systems safe.
3. Could this affect a small business?
If your organisation uses Microsoft Office SharePoint, especially on your own servers or hosted environments you manage, you could be affected. If you only use cloud-based SharePoint services managed by Microsoft, ask your provider if this issue is covered. Organisations not using SharePoint are not affected.
4. What to do now
- Check if your SharePoint installation is up to date with the latest security patches from Microsoft.
- If you do not manage your SharePoint environment, contact your IT provider or hosting service to confirm they have applied the necessary updates.
- Review user access rights to ensure only trusted individuals have permissions to use SharePoint features.
- Monitor your systems for any unusual activity and report concerns promptly to your IT support.
5. Ask your IT provider
Has the security update for CVE-2026-45659 been applied to our Microsoft SharePoint servers to protect against remote code execution attacks?
6. Bottom line
Apply the latest SharePoint security updates promptly to protect your organisation from serious remote attacks.
Information based on CISA KEV, NVD and reputable security news reporting.