CVE-2021-40049

What it actually does

The flaw permits unauthenticated network callers to bypass permission checks in the PMS module and retrieve sensitive system information.

Why it matters to the business

Attackers can obtain device or user data without credentials on millions of Huawei phones and tablets; the issue has been public for years with minimal observed exploitation activity.

How an attack unfolds

An attacker sends crafted requests directly to the PMS module over the network; missing authorization checks allow the retrieval of restricted system data without any user interaction or credentials.

How to fix it

Upgrade to the latest vendor-supplied firmware for EMUI, HarmonyOS or MagicUI that contains the PMS permission fix; apply security updates as soon as they are released by Huawei.

How to confirm the fix worked

Confirm the device is running a patched firmware build, then attempt the same unauthorized PMS requests from an external host and verify that access is denied.

Typical attack path

1. Locate an internet-facing or locally reachable Huawei device running affected EMUI, HarmonyOS or MagicUI
2. Send unauthenticated requests to the PMS module
3. Receive sensitive system information in the response

How to detect it

Review device and network logs for unexpected unauthenticated access attempts targeting PMS endpoints or unusually high volumes of system-information queries from external sources.

What your security team should do

• Inventory all Huawei mobile devices and schedule firmware updates
• Restrict network exposure of mobile devices where possible
• Monitor vendor security bulletins for PMS-related patches