CVE-2020-0041
Android Kernel Out-of-Bounds Write Vulnerability
Description
CVE-2020-0041 is a high-severity out-of-bounds write vulnerability in the Android Kernel's binder.c component, specifically in the binder_transaction function. The vulnerability is caused by an incorrect bounds check that allows local privilege escalation with no additional execution privileges needed and no user interaction required. CISA has added CVE-2020-0041 to its Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. This vulnerability was observed chained with CVE-2019-2215 and CVE-2020-0069 under the "AbstractEmu" exploit chain. With an EPSS score of 23.9% (95.9th percentile), the exploitation probability is significant.
KEV Information
CVSS Score
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| android | - |
Multiple CVSS Assessments
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
References
- https://source.android.com/security/bulletin/2020-03-01(Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-0041(Third Party Advisory, US Government Resource)
Weakness Type
CWE-20: Improper Input Validation
In the Android Kernel binder driver, the improper input validation manifests as an incorrect bounds check in the binder_transaction function of binder.c. The insufficient validation of transaction data allows an attacker to write data beyond the intended buffer boundaries, leading to out-of-bounds memory corruption that can be leveraged for privilege escalation.
Learn more: CWE-20 — Improper Input Validation
Impact Analysis
CVE-2020-0041 carries a CVSS 3.1 score of 7.8 (HIGH), representing a serious local privilege escalation vulnerability. The attack is locally exploitable with low complexity, requiring low privileges and no user interaction. Successful exploitation results in high impact across confidentiality, integrity, and availability, enabling an attacker to escalate privileges from a standard application to kernel level. The EPSS score of 23.9% indicates a significant probability of exploitation activity. As part of the AbstractEmu exploit chain alongside CVE-2019-2215 and CVE-2020-0069, this vulnerability has been used to achieve complete device compromise on Android systems, making it a practical threat to all unpatched Android devices.
Exploit Maturity
CVE-2020-0041 is confirmed as actively exploited through its listing in the CISA Known Exploited Vulnerabilities catalog. The vulnerability was observed as a key component of the "AbstractEmu" exploit chain, where it was chained with CVE-2019-2215 (a use after free in binder.c) and CVE-2020-0069 (a MediaTek Command Queue driver vulnerability) to achieve full privilege escalation on Android devices. The EPSS score of 23.9% (95.9th percentile) indicates a significant probability of ongoing exploitation. While no standalone public exploit was identified in the references, the documented use in the AbstractEmu framework demonstrates that reliable exploitation techniques exist and are actively employed by threat actors.
Remediation
- Apply Android security updates immediately as mandated by CISA KEV: Apply updates per vendor instructions. Google addressed this vulnerability in the March 2020 Android Security Bulletin.
- Verify that all Android devices are running security patches dated March 2020 or later, which include the fix for Android ID A-145988638 addressing the binder_transaction bounds check.
- For devices that no longer receive vendor updates, implement mobile device management controls to restrict application installation to trusted sources and minimize the attack surface for local exploitation.
- Monitor for indicators of the AbstractEmu exploit chain, including unusual binder activity patterns, unexpected privilege escalation, and signs of root access by non-system processes.
- Conduct a thorough inventory of all Android devices in your environment and prioritize patching based on device exposure and the availability of security updates from the device manufacturer.
Technical Details
CVE-2020-0041 is an out-of-bounds write vulnerability in the binder_transaction function of binder.c within the Android Kernel. The root cause is an incorrect bounds check that fails to properly validate transaction data, allowing writes beyond the intended buffer boundaries. The CVSS vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H confirms local exploitation with low privileges, low complexity, and no user interaction. The CWE-20 (Improper Input Validation) classification reflects the insufficient bounds checking that enables the out-of-bounds write. This vulnerability was specifically designed to be chained with CVE-2019-2215 and CVE-2020-0069 in the AbstractEmu exploit framework, where each vulnerability in the chain contributes a different capability toward achieving full kernel-level privilege escalation.
Frequently Asked Questions
Is CVE-2020-0041 being actively exploited?
Yes. CVE-2020-0041 is listed in the CISA Known Exploited Vulnerabilities catalog, confirming active exploitation. It was observed as part of the AbstractEmu exploit chain targeting Android devices, combined with CVE-2019-2215 and CVE-2020-0069.
What products are affected by CVE-2020-0041?
CVE-2020-0041 affects Google Android devices running kernel versions prior to the March 2020 security patch level. The vulnerability is in the binder driver, a core Android kernel component used by all Android devices.
How do I fix CVE-2020-0041?
Apply the Android security updates from the March 2020 Security Bulletin, which addresses the binder_transaction bounds check issue (Android ID A-145988638). For devices no longer receiving updates, restrict app installation to trusted sources and implement MDM controls.
How severe is CVE-2020-0041?
CVE-2020-0041 has a CVSS 3.1 score of 7.8 (HIGH) and an EPSS score of 23.9% (95.9th percentile). The vulnerability enables local privilege escalation to kernel level and is used in the AbstractEmu exploit chain for complete Android device compromise.
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