Microsoft SharePoint Weak Authentication Vulnerability: Early Warning
- Severity
- HIGH
- Affected component
- microsoft-sharepoint (npm)
- Patched version
- Not yet available
Microsoft SharePoint reportedly contains a weak authentication vulnerability which allows unauthorized network access. Users of Microsoft SharePoint are advised to take immediate action.
What happened
An early warning has been issued regarding a high-severity vulnerability in Microsoft SharePoint. This vulnerability, tracked as CVE-2026-55040, allows an unauthorized attacker to bypass a security feature over a network. The exploit is reportedly being used in the wild. Users should review their network security configurations and upgrade to the latest version of Microsoft SharePoint as soon as possible.
The vulnerability was first flagged on 2026-08-18T00:00:00+00:00. No authoritative version range has been published yet. Users are encouraged to consult primary sources for the most current information.
What to do about it
- Upgrade to the latest version of Microsoft SharePoint.
- Review and strengthen your network security configurations.
- Monitor primary sources for updates on the vulnerability and any official fixes.
- No official fix has been published yet. Monitor the sources below for updates.
How 0Day would have caught this
microsoft-sharepoint is anywhere in your dependency tree, the engineers who own the affected repositories get a push alert the moment it is flagged — no manual audit to remember to run.Read how this differs from waiting on a scanner to catch a known advisory, or see the exact, read-only access 0Day needs to do this for an organization.
Frequently asked questions
Am I affected?
If you are using Microsoft SharePoint, you may be affected. No authoritative version range has been published yet.
What should I do right now?
Upgrade to the latest version of Microsoft SharePoint and review your network security configurations.
Has this been exploited in the wild?
Yes, the exploit is reportedly being used in the wild.