CVE-2020-16010
Google Chrome for Android UI Heap Buffer Overflow Vulnerability
Description
CVE-2020-16010 is a CRITICAL heap buffer overflow vulnerability affecting Google Chrome for Android UI component, carrying a CVSS 3.1 score of 9.6. A heap buffer overflow in the UI component of Google Chrome on Android prior to 86.0.4240.185 allows a remote attacker who has already compromised the renderer process to potentially perform a sandbox escape via a crafted HTML page. This CVE is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog with a remediation deadline of 2022-05-03. With an EPSS score of 0.24113 (95.981st percentile), this vulnerability demonstrates very high real-world exploitation activity and was exploited as a zero-day in the wild.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:HOpen in CalculatorCWEs
Affected Products
| Vendor | Product | Version |
|---|---|---|
| chrome | < 86.0.4240.185 |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
References
- https://chromereleases.googleblog.com/2020/11/chrome-for-android-update.html(Vendor Advisory)
- https://crbug.com/1144368(Issue Tracking, Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-16010(US Government Resource)
Weakness Type
CWE-787: Out-of-bounds Write
CVE-2020-16010 is classified under CWE-787 — Out-of-bounds Write. Out-of-bounds Write occurs when software writes data to a memory location outside the intended boundaries of a buffer. This can happen through buffer overflows, incorrect array indexing, pointer arithmetic errors, or integer overflows affecting size calculations. Out-of-bounds writes are extremely dangerous as they can corrupt adjacent data, overwrite control flow information, modify security flags, or corrupt heap metadata.
In the context of Chrome's Android UI component, this heap buffer overflow enables an attacker who has already compromised the renderer sandbox to escape the sandbox entirely. This makes it a critical second stage in an exploit chain, as the renderer compromise provides the initial foothold and this vulnerability provides the sandbox escape needed for full device compromise.
Learn more: CWE-787 — Out-of-bounds Write
Impact Analysis
CVE-2020-16010 carries a CVSS 3.1 score of 9.6 (CRITICAL) with Changed Scope.
Confidentiality (HIGH): Successful sandbox escape grants the attacker access to data outside the Chrome renderer sandbox, including other application data, user files, and potentially system-level information on the Android device.
Integrity (HIGH): The attacker can modify data beyond the Chrome sandbox boundary, potentially installing malware, modifying application data, or altering system configurations on the compromised Android device.
Availability (HIGH): Complete disruption of the browser and potentially the underlying Android system is possible through the sandbox escape, including persistent denial of service or device instability.
Scope Changed: The Changed scope is critical — it indicates that the vulnerability allows the attacker to break out of the Chrome renderer sandbox and impact resources beyond the originally vulnerable component, affecting the broader Android system.
With an EPSS score of 0.24113 (95.981st percentile), this vulnerability ranks among the most likely to be exploited, confirmed by its use as a zero-day in targeted attacks.
Exploit Maturity
CVE-2020-16010 has confirmed active exploitation as a zero-day vulnerability and is listed in CISA's Known Exploited Vulnerabilities catalog.
Exploit status: This vulnerability was discovered being exploited in the wild before a patch was available, making it a true zero-day. Google's Threat Analysis Group (TAG) reported the in-the-wild exploitation. The vulnerability was part of an exploit chain targeting Chrome on Android devices, where an initial renderer compromise was chained with this sandbox escape.
Ransomware association: No direct ransomware association has been confirmed for CVE-2020-16010 as of the latest KEV data. However, the mobile-focused nature of this exploit suggests use in targeted surveillance or espionage operations rather than traditional ransomware campaigns.
Attack surface: The vulnerability targets Chrome on Android, which has a massive global user base. Exploitation requires the attacker to first compromise the renderer process, meaning this is typically used as part of a multi-stage exploit chain rather than as a standalone vulnerability.
KEV deadline: CISA required federal agencies to remediate this vulnerability by 2022-05-03. All organizations should ensure Chrome on Android devices is updated to version 86.0.4240.185 or later.
Remediation
- Update Google Chrome on Android immediately. Ensure all Android devices are running Chrome version 86.0.4240.185 or later. Enable automatic updates in the Google Play Store to receive security patches promptly.
- Implement mobile device management (MDM) policies. Use MDM solutions to enforce Chrome version requirements across managed Android devices. Configure policies to prevent users from disabling automatic updates.
- Monitor for exploit chain indicators. Since this vulnerability requires prior renderer compromise, monitor for signs of initial exploitation including suspicious web page loads, unusual Chrome crashes, or unexpected network connections from Chrome processes.
- Restrict access to untrusted websites on managed devices. Implement web filtering to reduce exposure to potentially malicious pages that could initiate the exploit chain targeting this vulnerability.
- Review Android device security posture. Ensure Android devices have up-to-date security patches at both the OS and application levels. Enable Google Play Protect for additional malware scanning.
- Educate users about mobile security. Train users to avoid clicking suspicious links and to keep their browsers updated, particularly on mobile devices where exploit chains targeting browsers are increasingly common.
Technical Details
CVE-2020-16010 is a CRITICAL-severity heap buffer overflow in the UI component of Google Chrome on Android. The vulnerability can be exploited remotely via a crafted HTML page, but requires that the attacker has already compromised the renderer process.
Technical mechanism: The heap buffer overflow occurs in Chrome's Android UI layer. When processing certain UI-related operations triggered by crafted HTML content, Chrome fails to properly validate buffer boundaries, writing data beyond the allocated heap buffer. An attacker who has already achieved code execution within the renderer sandbox can leverage this overflow to corrupt heap metadata or adjacent objects, ultimately escaping the Chrome sandbox.
Exploit chain context: This vulnerability was used as part of a multi-stage exploit chain. The first stage compromises the Chrome renderer process (typically via a separate vulnerability), and CVE-2020-16010 then provides the sandbox escape. The Changed scope in the CVSS vector reflects this sandbox escape capability.
CVSS 3.1 vector analysis: The vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H indicates a network-accessible attack requiring user interaction (visiting a malicious page) with no privileges required. The Changed scope reflects the sandbox escape, and all three impact metrics are HIGH.
Affected versions: Google Chrome for Android prior to version 86.0.4240.185.
Frequently Asked Questions
Is CVE-2020-16010 being actively exploited?
Yes, CVE-2020-16010 was exploited as a zero-day in the wild before a patch was available. Google's Threat Analysis Group confirmed the in-the-wild exploitation. The vulnerability was used as part of a multi-stage exploit chain targeting Chrome on Android devices, typically for targeted surveillance operations.
What products are affected by CVE-2020-16010?
Google Chrome for Android prior to version 86.0.4240.185 is affected. This specifically impacts the Android version of Chrome and its UI component. Desktop versions of Chrome are not affected by this particular vulnerability. Organizations should verify all managed Android devices are running the patched version.
How do I fix CVE-2020-16010?
Update Google Chrome on all Android devices to version 86.0.4240.185 or later. Enable automatic updates through the Google Play Store. For managed device environments, use MDM solutions to enforce Chrome version requirements and verify patch deployment across the fleet.
How severe is CVE-2020-16010?
CVE-2020-16010 is rated CRITICAL with a CVSS score of 9.6 and a Changed scope, indicating sandbox escape capability. The EPSS score of 0.24113 (95.981st percentile) confirms extremely high exploitation likelihood. As a confirmed zero-day used in targeted attacks, this vulnerability requires immediate attention on all Android devices running Chrome.
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