CVE-2020-16013
Google Chromium V8 Incorrect Implementation Vulnerabililty
Description
CVE-2020-16013 is a HIGH inappropriate implementation 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. This flaw affects multiple web browsers that utilize Chromium, including Google Chrome, Microsoft Edge, and Opera. The primary affected product is Google Chrome (< 86.0.4240.198). 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 0.26139 (96.21st percentile), this vulnerability demonstrates significant 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 CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| chrome | < 86.0.4240.198 |
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
- https://chromereleases.googleblog.com/2020/11/stable-channel-update-for-desktop_11.html(Release Notes, Vendor Advisory)
- https://crbug.com/1147206(Permissions Required, Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-16013(US Government Resource)
Weakness Type
CWE-787: Out-of-Bounds Write
CVE-2020-16013 is classified under CWE-787 — Out-of-Bounds Write. This weakness occurs when software writes data past the end, or before the beginning, of the intended buffer. The inappropriate implementation in V8 leads to heap corruption scenarios where the JavaScript engine writes to memory locations outside the intended boundaries. Out-of-bounds write vulnerabilities in browser JavaScript engines are particularly critical because they can be triggered remotely by simply visiting a malicious website.
In the context of Google Chromium's V8 engine, this weakness manifests through an incorrect implementation in the engine's code generation or interpretation pipeline. The flaw allows specially crafted JavaScript to trigger memory writes beyond allocated boundaries, leading to heap corruption. Attackers can exploit this corruption to gain control over program execution flow, enabling arbitrary code execution within the browser's renderer process. V8 implementation flaws are especially dangerous because the engine processes untrusted JavaScript code from any website the user visits.
Learn more: CWE-787 — Out-of-Bounds Write
Impact Analysis
CVE-2020-16013 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 within the Chromium renderer process, including page content, cookies, session tokens, and form data.
Integrity (HIGH): Attackers can modify memory within the browser process to inject malicious code, alter web page content, or manipulate browser behavior to perform unauthorized actions.
Availability (HIGH): Complete disruption of the browser process is possible through heap corruption, causing crashes, data loss, or persistent browser instability.
Scope Unchanged: The vulnerability's scope is Unchanged (U), meaning exploitation is contained within the V8 renderer process. To achieve full system compromise, this vulnerability would need to be chained with a sandbox escape.
With an EPSS score of 0.26139 (96.21st percentile), this vulnerability has a high probability of being exploited in real-world attacks.
Exploit Maturity
CVE-2020-16013 has confirmed active exploitation in the wild and is listed in CISA's Known Exploited Vulnerabilities catalog.
Exploit status: This vulnerability was exploited as a zero-day in the wild. Google confirmed active exploitation in the November 2020 stable channel update advisory, where it was patched alongside CVE-2020-16017 (a use-after-free in site isolation). The EPSS score of 0.26139 (96.21st percentile) confirms high real-world exploitation probability.
Ransomware association: As of the latest KEV data, no direct ransomware association has been confirmed for CVE-2020-16013. However, the confirmed zero-day exploitation indicates that advanced threat actors have been targeting this vulnerability.
Attack surface: This vulnerability was discovered being exploited alongside CVE-2020-16017, indicating it was part of an exploit chain where V8 heap corruption (this CVE) provided the initial code execution, and the site isolation use-after-free enabled sandbox escape. Organizations should assume that complete exploit chains exist.
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 86.0.4240.198 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 in your infrastructure running versions prior to Google Chrome 86.0.4240.198. Use asset inventory and vulnerability scanning tools to ensure no instances are missed.
- Update all Chromium-based browsers. Since this vulnerability affects the V8 engine in Chromium, ensure all browsers and applications embedding Chromium are updated to versions containing the fix.
- Implement interim mitigations if patching is delayed. If immediate patching is not feasible, consider restricting JavaScript execution for untrusted content, implementing browser isolation, and applying network-level controls.
- Scan for signs of prior exploitation. Given the confirmed zero-day exploitation and use in exploit chains, conduct a thorough investigation for indicators of compromise including unusual browser process behavior and signs of sandbox escape.
- Update detection signatures and monitoring rules. Ensure endpoint detection tools, browser security controls, and SIEM rules are updated to detect exploitation attempts targeting V8 inappropriate implementation vulnerabilities.
Technical Details
CVE-2020-16013 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 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 stems from an inappropriate implementation in V8, Google Chrome's JavaScript engine. The flaw exists in how V8 processes certain JavaScript operations, leading to incorrect memory handling that can result in heap corruption. When an attacker crafts JavaScript that triggers this inappropriate implementation, V8 performs memory operations with incorrect parameters, writing data beyond intended buffer boundaries. This heap corruption can be weaponized to achieve arbitrary code execution within the Chromium renderer process.
Exploit chain context: This vulnerability was discovered being exploited alongside CVE-2020-16017 (use-after-free in site isolation), forming a two-stage exploit chain: CVE-2020-16013 provides initial code execution through V8 heap corruption, and CVE-2020-16017 enables sandbox escape.
Affected products: Google Chrome (< 86.0.4240.198)
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-2020-16013 being actively exploited?
Yes, CVE-2020-16013 was exploited as a zero-day vulnerability in the wild. Google confirmed active exploitation in their November 2020 security advisory. This vulnerability was used alongside CVE-2020-16017 as part of an exploit chain. The EPSS score of 0.26139 (96.21st percentile) confirms high exploitation probability.
Which products are affected by CVE-2020-16013?
The primary affected product is Google Chrome versions prior to 86.0.4240.198. Since the vulnerability is in the V8 JavaScript engine, other Chromium-based browsers including Microsoft Edge and Opera may also be affected if running vulnerable Chromium versions.
How do I fix CVE-2020-16013?
Update Google Chrome to version 86.0.4240.198 or later. This update also fixes CVE-2020-16017, which was exploited together with this vulnerability. For other Chromium-based browsers, apply the corresponding vendor updates. Verify all instances are patched using vulnerability scanning.
How severe is CVE-2020-16013?
CVE-2020-16013 is rated HIGH with a CVSS 3.1 score of 8.8. Its EPSS score of 0.26139 places it in the 96.21st percentile for exploitation likelihood. The vulnerability was exploited as a zero-day as part of an exploit chain with CVE-2020-16017. The CISA remediation deadline was 2022-05-03.
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