CVE-2020-15999 – This CVE describes a heap buffer overflow vulne... (How to Fix)

Q: What is the severity of CVE-2020-15999?

CVE-2020-15999 has a CVSS score of 9.6 (CRITICAL). This CVE describes a heap buffer overflow vulnerability in the Freetype font rendering library used by Google Chrome. A remote attacker could exploit this by tricking users into visiting a malicious HTML page, potentially leading to arbitrary code execution or browser crashes. All users of affected Chrome versions are at risk.

📋 TL;DR

This CVE describes a heap buffer overflow vulnerability in the Freetype font rendering library used by Google Chrome. A remote attacker could exploit this by tricking users into visiting a malicious HTML page, potentially leading to arbitrary code execution or browser crashes. All users of affected Chrome versions are at risk.

💻 Affected Systems

Products:

Google Chrome
Chromium-based browsers
Applications using Freetype library

Versions: Chrome versions prior to 86.0.4240.111

Operating Systems: Windows, macOS, Linux, Android, Chrome OS

Default Config Vulnerable: ⚠️ Yes

Notes: All standard Chrome installations are vulnerable. The vulnerability is in Freetype library which may affect other software using it.

📦 What is this software?

Backports Sle by Opensuse

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Chrome by Google

Google Chrome is the world's most popular web browser, used by over 3 billion users globally across Windows, macOS, Linux, Android, and iOS platforms. As a Chromium-based browser developed by Google, Chrome dominates the browser market with approximately 65% market share, making it a critical compon...

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⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution with the same privileges as the Chrome process, potentially leading to full system compromise if Chrome is running with elevated privileges.

🟠

Likely Case

Browser crash (denial of service) or limited code execution within Chrome's sandbox, potentially allowing data theft or further exploitation.

🟢

If Mitigated

Browser crash with no data compromise if sandboxing works correctly, or blocked exploit attempt if security controls detect malicious activity.

🌐 Internet-Facing: HIGH - Attackers can host malicious HTML pages on websites accessible via the internet.

🏢 Internal Only: MEDIUM - Risk exists if users visit internal web pages with malicious content, but requires attacker access to internal systems.

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: LIKELY

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires user interaction (visiting malicious page). Technical details and proof-of-concept are publicly available.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 86.0.4240.111 and later

Vendor Advisory: https://chromereleases.googleblog.com/2020/10/stable-channel-update-for-desktop_20.html

Restart Required: Yes

Instructions:

1. Open Chrome. 2. Click the three-dot menu. 3. Go to Help > About Google Chrome. 4. Chrome will automatically check for and install updates. 5. Click 'Relaunch' to restart Chrome with the update.

🔧 Temporary Workarounds

Disable JavaScript

all

Temporarily disable JavaScript to prevent malicious HTML from executing exploit code

chrome://settings/content/javascript

Use Chrome's Site Isolation

all

Enable site isolation to limit impact of potential exploitation

chrome://flags/#enable-site-per-process

🧯 If You Can't Patch

Restrict web browsing to trusted sites only
Use alternative browser temporarily until patching is possible

🔍 How to Verify

Check if Vulnerable:

Check Chrome version in Settings > About Chrome. If version is below 86.0.4240.111, system is vulnerable.

Check Version:

chrome://version/ or 'google-chrome --version' on Linux/macOS command line

Verify Fix Applied:

Verify Chrome version is 86.0.4240.111 or higher in Settings > About Chrome.

📡 Detection & Monitoring

Log Indicators:

Chrome crash reports
Unexpected process termination
Memory access violation errors

Network Indicators:

Requests to suspicious domains hosting HTML with font files
Unusual font file downloads

SIEM Query:

source="chrome" AND (event_type="crash" OR message="*buffer overflow*" OR message="*freetype*")

📊 Metadata

CVE ID: CVE-2020-15999

CVSS v3 Score: 9.6 (CRITICAL)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

CWE: CWE-787

Published: November 3, 2020

Last Updated: October 24, 2025

🔗 References

http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00016.html Broken Link,Mailing List,Third Party Advisory
http://seclists.org/fulldisclosure/2020/Nov/33 Mailing List,Not Applicable,Third Party Advisory
https://chromereleases.googleblog.com/2020/10/stable-channel-update-for-desktop_20.html Third Party Advisory
https://crbug.com/1139963 Exploit,Issue Tracking,Third Party Advisory
https://googleprojectzero.blogspot.com/p/rca-cve-2020-15999.html Exploit,Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/J3QVIGAAJ4D62YEJAJJWMCCBCOQ6TVL7/ Release Notes
https://security.gentoo.org/glsa/202011-12 Third Party Advisory
https://security.gentoo.org/glsa/202012-04 Third Party Advisory
https://security.gentoo.org/glsa/202401-19 Third Party Advisory
https://www.debian.org/security/2021/dsa-4824 Mailing List,Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00016.html Broken Link,Mailing List,Third Party Advisory
http://seclists.org/fulldisclosure/2020/Nov/33 Mailing List,Not Applicable,Third Party Advisory
https://chromereleases.googleblog.com/2020/10/stable-channel-update-for-desktop_20.html Third Party Advisory
https://crbug.com/1139963 Exploit,Issue Tracking,Third Party Advisory
https://googleprojectzero.blogspot.com/p/rca-cve-2020-15999.html Exploit,Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/J3QVIGAAJ4D62YEJAJJWMCCBCOQ6TVL7/ Release Notes
https://security.gentoo.org/glsa/202011-12 Third Party Advisory
https://security.gentoo.org/glsa/202012-04 Third Party Advisory
https://security.gentoo.org/glsa/202401-19 Third Party Advisory
https://security.netapp.com/advisory/ntap-20240812-0001/ 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-2020-15999 US Government Resource

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🔗 Related Vulnerabilities

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