CVE-2020-16009
Google Chromium V8 Type Confusion Vulnerability
Description
CVE-2020-16009 is a HIGH type confusion vulnerability in Google Chromium's V8 JavaScript engine, carrying a CVSS 3.1 score of 8.8. The vulnerability allows a remote attacker to potentially exploit heap corruption via a crafted HTML page by exploiting an inappropriate implementation in V8. This flaw affects multiple web browsers that utilize Chromium, including Google Chrome, Microsoft Edge, and Opera. Affected products include Google Chrome (< 86.0.4240.183), Microsoft Edge (< 86.0.622.63), CefSharp (< 86.0.241), and multiple Linux distributions. 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 0.84383 (99.31st percentile), this vulnerability demonstrates extremely high real-world exploitation activity and should be prioritized for immediate remediation.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HOpen in CalculatorCWEs
Affected Products
| Vendor | Product | Version |
|---|---|---|
| cefsharp | cefsharp | < 86.0.241 |
| chrome | < 86.0.4240.183 | |
| microsoft | edge | < 86.0.622.63 |
| microsoft | edge chromium | < 86.0.4240.183 |
| opensuse | backports sle | 15.0 |
| opensuse | leap | 15.1; 15.2 |
| fedoraproject | fedora | 32; 33 |
| debian | debian linux | 10.0 |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
References
- http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00016.html(Broken Link, Mailing List, Third Party Advisory)
- http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00017.html(Broken Link, Mailing List, Third Party Advisory)
- http://packetstormsecurity.com/files/159974/Chrome-V8-Turbofan-Type-Confusion.html(Exploit, Third Party Advisory, VDB Entry)
- https://chromereleases.googleblog.com/2020/11/stable-channel-update-for-desktop.html(Release Notes, Vendor Advisory)
- https://crbug.com/1143772(Exploit, Issue Tracking)
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/S4XYJ7B6OXHZNYSA5J3DBUOFEC6WCAGW/(Release Notes)
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SC3U3H6AISVZB5PLZLLNF4HMQ4UFFL7M/(Release Notes)
- https://security.gentoo.org/glsa/202011-12(Third Party Advisory)
- https://www.debian.org/security/2021/dsa-4824(Mailing List, Third Party Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-16009(US Government Resource)
Weakness Type
CWE-843: Access of Resource Using Incompatible Type (Type Confusion)
CVE-2020-16009 is classified under CWE-843 — Access of Resource Using Incompatible Type (Type Confusion) and CWE-787 — Out-of-Bounds Write. Type confusion occurs when a program accesses a resource using an incompatible type, leading to undefined behavior. In JavaScript engines like V8, type confusion vulnerabilities arise when the JIT (Just-In-Time) compiler makes incorrect assumptions about object types during optimization, allowing attackers to read or write memory at unexpected locations.
In the context of Google Chromium's V8 engine, this weakness is particularly dangerous because V8's Turbofan JIT compiler performs aggressive speculative optimizations. When type assumptions are violated, the generated machine code can operate on memory with incorrect type information, leading to heap corruption. Attackers can craft JavaScript code that triggers type confusion in Turbofan, enabling them to construct arbitrary read/write primitives and ultimately achieve code execution within the renderer process.
Learn more: CWE-843 — Access of Resource Using Incompatible Type
Impact Analysis
CVE-2020-16009 carries a CVSS 3.1 score of 8.8 (HIGH) with Unchanged Scope.
Confidentiality (HIGH): Successful exploitation grants the attacker extensive access to sensitive data processed by the Chromium browser, including page content, cookies, session tokens, and potentially saved passwords or autofill data accessible to the renderer process.
Integrity (HIGH): Attackers can modify memory within the browser process, inject malicious code, alter page content, or manipulate browser state to perform actions on behalf of the user.
Availability (HIGH): Complete disruption of the browser process is possible, including crashes, arbitrary process termination, or persistent denial of service through corrupted browser state.
Scope Unchanged: The vulnerability's scope is Unchanged (U), meaning exploitation is contained within the Chromium renderer process. However, when combined with sandbox escape vulnerabilities, the impact can extend to the entire system.
With an EPSS score of 0.84383 (99.31st percentile), this vulnerability ranks among the most actively exploited vulnerabilities tracked, underscoring the critical urgency of remediation.
Exploit Maturity
CVE-2020-16009 has confirmed active exploitation in the wild and is listed in CISA's Known Exploited Vulnerabilities catalog.
Exploit status: This vulnerability has been actively exploited in the wild, as confirmed by Google's Threat Analysis Group and its inclusion in the KEV catalog. Public exploit code is available on Packet Storm Security, demonstrating Chrome V8 Turbofan type confusion techniques. The EPSS score of 0.84383 (99.31st percentile) places it among the most exploited vulnerabilities tracked.
Ransomware association: As of the latest KEV data, no direct ransomware association has been confirmed for CVE-2020-16009. However, the availability of public exploit code and the high EPSS score indicate widespread threat actor interest.
Attack surface: Public exploit code demonstrates V8 Turbofan type confusion exploitation. The vulnerability was exploited in the wild as a zero-day before patches were available. Organizations should assume that sophisticated threat actors have refined exploitation tools beyond what is publicly available.
KEV deadline: CISA required federal agencies to remediate this vulnerability by 2022-05-03. All organizations should treat this deadline as a strong recommendation for their own remediation timelines.
Remediation
- Apply vendor patches immediately. Update Google Chrome to version 86.0.4240.183 or later. Consult the vendor advisory at chromereleases.googleblog.com for specific patch guidance.
- Verify affected product versions in your environment. Identify all instances of Chromium-based browsers and embedded frameworks: Google Chrome (< 86.0.4240.183), Microsoft Edge (< 86.0.622.63), CefSharp (< 86.0.241), and any other Chromium-based applications.
- Update all Chromium-based browsers and frameworks. Since this vulnerability affects the V8 engine in Chromium, ensure all applications embedding Chromium or V8 are updated, including Electron-based applications.
- Implement interim mitigations if patching is delayed. If immediate patching is not feasible, consider disabling JavaScript execution for untrusted content, restricting access to high-risk websites, and enabling site isolation features.
- Scan for signs of prior exploitation. Given the public availability of exploit code and confirmed exploitation, review security logs for evidence of browser-based attacks, unusual process behavior, or indicators of compromise.
- Update detection signatures and monitoring rules. Ensure endpoint detection tools, web proxies, and SIEM rules are updated to detect exploitation attempts targeting V8 type confusion vulnerabilities.
Technical Details
CVE-2020-16009 is a HIGH-severity vulnerability in Google Chromium's V8 JavaScript engine that can be exploited remotely over the network. The attack complexity is low, meaning no specialized conditions or preparation are required. No prior authentication or privileges are needed. User interaction is required, meaning a victim must visit a malicious web page.
Technical mechanism: The vulnerability exists in V8's Turbofan JIT compiler, which performs speculative type optimizations on JavaScript code. An attacker can craft JavaScript that causes Turbofan to make incorrect type assumptions during compilation. When the optimized machine code executes with objects of unexpected types, it performs memory operations with incorrect offsets and sizes, leading to heap corruption. This can be leveraged to construct arbitrary memory read/write primitives, ultimately enabling code execution within the Chromium renderer process.
Affected products: Google Chrome (< 86.0.4240.183), Microsoft Edge (< 86.0.622.63), Microsoft Edge Chromium (< 86.0.4240.183), Cefsharp Cefsharp (< 86.0.241), Opensuse Backports Sle (15.0), Opensuse Leap (15.1; 15.2), Fedora (32; 33), Debian Linux (10.0)
CVSS 3.1 vector analysis: The vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H reflects a network-based attack with low complexity, no privileges required, user interaction required, unchanged scope, and maximum impact across all three CIA dimensions.
Frequently Asked Questions
Is CVE-2020-16009 being actively exploited?
Yes, CVE-2020-16009 has been actively exploited in the wild as a zero-day vulnerability. Google's Threat Analysis Group reported in-the-wild exploitation before the patch was available. Public exploit code demonstrating V8 Turbofan type confusion is available. The EPSS score of 0.84383 (99.31st percentile) confirms extremely high exploitation likelihood.
Which products are affected by CVE-2020-16009?
The primary affected products include Google Chrome (< 86.0.4240.183), Microsoft Edge (< 86.0.622.63), CefSharp (< 86.0.241), and any Chromium-based browser or application using V8 versions prior to the fix. Linux distributions including Fedora, Debian, and openSUSE are also affected through their Chromium packages.
How do I fix CVE-2020-16009?
Update Google Chrome to version 86.0.4240.183 or later. For Microsoft Edge, update to version 86.0.622.63 or later. For CefSharp, update to version 86.0.241 or later. For all other Chromium-based applications, ensure the embedded Chromium/V8 engine is updated to a version containing the fix.
How severe is CVE-2020-16009?
CVE-2020-16009 is rated HIGH with a CVSS 3.1 score of 8.8. Its EPSS score of 0.84383 places it in the 99.31st percentile for exploitation likelihood. Public exploit code exists, and the vulnerability was exploited as a zero-day. The CISA remediation deadline was 2022-05-03.
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