Auth bypass in Google Android
CVE-2021-39810
In verifyDefaults of CardEmulationManager.java, there is a possible way to set a third party app as the default contactless payment app without user consent due to a missing permission check. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.001 (1.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 1st percentile — 1.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: 0.000
Affected products
- Google Android — versions 13, 13.0
Weakness classification (CWE)
References
- source.android.com/security/bulletin/2025-09-01 (Vendor Advisory)
- af854a3a-2127-422b-91ae-364da2661108 (Release Notes, Vendor Advisory)
Frequently asked questions
- What is CVE-2021-39810?
- CVE-2021-39810 is a high-severity vulnerability in Google Android, classified under Missing Authorization. CVSS score: 7.8/10. Published 2023-10-30.
- How severe is CVE-2021-39810?
- High severity. CVSS v3 base score is 7.8 out of 10.