CVE-2021-0520 Use after free in Android

What is CVE-2021-0520?

CVE-2021-0520 is a high-severity use after free vulnerability in Google Android, published on 21 Jun 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In several functions of MemoryFileSystem.cpp and related files, there is a possible use after free due to a race condition. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-11 Android-10Android ID: A-176237595

Weakness: CWE-416, CWE-362

Which versions are affected by CVE-2021-0520?

It affects 1 product.

Products include Google Android.

How do I fix CVE-2021-0520?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2021-0520 being exploited?

There is no known exploitation of CVE-2021-0520 in the wild and no public exploit code.

Public exploit code: 2 proofs of concept on GitHub.

Other vulnerabilities in Google Android

• CVE-2026-58704 Google Pixel Improper Authorization Exploited High 8.8
• CVE-2025-48543 Android Runtime Use-After-Free Exploited High 8.8
• CVE-2023-35674 Android Framework Privilege Escalation Exploited High 8.8
• CVE-2025-48595 Android Framework Integer Overflow Exploited High 8.4
• CVE-2024-32896 Android Pixel Privilege Escalation Exploited High 8.1

All Google Android vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as A-176237595, ASB-A-176237595, GHSA-pmm6-qxj3-9jr6.