CVE-2020-15994 Overview
CVE-2020-15994 is a use-after-free vulnerability in the V8 JavaScript engine used by Google Chrome versions prior to 86.0.4240.99. A remote attacker can exploit heap corruption by serving a crafted HTML page to a user. Successful exploitation can lead to arbitrary code execution within the renderer process. The flaw is tracked under [CWE-416] and affects both Chrome desktop and Chrome for Android builds. Google addressed the issue in the October 2020 Chrome for Android stable channel update.
Critical Impact
A crafted web page can trigger heap corruption in V8, enabling a remote attacker to compromise the confidentiality, integrity, and availability of the affected browser session.
Affected Products
- Google Chrome versions prior to 86.0.4240.99
- Google Chrome for Android prior to 86.0.4240.99
- Google Android builds shipping vulnerable Chrome packages
Discovery Timeline
- 2020-11-03 - CVE-2020-15994 published to NVD
- 2024-11-21 - Last updated in NVD database
Technical Details for CVE-2020-15994
Vulnerability Analysis
The defect resides in V8, the open-source JavaScript and WebAssembly engine that compiles and executes script in Chrome. V8 manages JavaScript objects on its own garbage-collected heap. A use-after-free condition occurs when code retains a reference to an object after that object has been freed or relocated by the engine. Subsequent access through the dangling reference allows an attacker to read or write memory that has been repurposed for other content.
In the context of V8, attacker-controlled JavaScript executed inside an HTML page can manipulate object lifetimes to reach the corrupted state. The result is heap corruption that an exploit can shape into a type confusion or controlled write primitive. Combined with a sandbox escape, such primitives have historically led to full renderer compromise on Chrome targets.
Root Cause
The root cause is improper lifetime management of a V8 heap object [CWE-416]. The engine releases or moves the underlying allocation while a reference path remains reachable from script. The original Chromium tracker entry is restricted, but Google's fix is shipped as part of the V8 component update bundled with the Chrome 86.0.4240.99 release. See the Chromium Bug Report #1117258 for additional disclosure detail.
Attack Vector
Exploitation requires user interaction: the victim must load a crafted HTML page in a vulnerable Chrome build. No authentication is required, and the attack traverses the network. Delivery typically involves a malicious site, a compromised legitimate site, or a malicious iframe served through ad networks. The vulnerability does not require local access or elevated privileges.
No public proof-of-concept exploit is listed for CVE-2020-15994 in Exploit-DB or vendor PoC repositories. The EPSS data places the probability of exploitation activity in the 89th percentile, reflecting the historical attractiveness of V8 use-after-free flaws to exploit developers.
No verified exploit code is published for this CVE. Refer to the Chromium Bug Report #1117258 for technical context once Google releases the restricted entry.
Detection Methods for CVE-2020-15994
Indicators of Compromise
- Chrome renderer process crashes referencing V8 heap or garbage collector frames around the time of suspect web activity.
- Unexpected child processes spawned by chrome.exe or the Android Chrome package following navigation to an unfamiliar domain.
- Outbound connections from the browser process to attacker-controlled infrastructure shortly after page load.
Detection Strategies
- Inventory installed Chrome versions across managed endpoints and flag any build below 86.0.4240.99.
- Hunt for browser crash dumps in %LOCALAPPDATA%\Google\Chrome\User Data\Crashpad and correlate with the URLs visited at the time of the crash.
- Apply web proxy or DNS telemetry to identify users who navigated to known malicious or newly registered domains delivering JavaScript-heavy payloads.
Monitoring Recommendations
- Forward endpoint process, network, and crash telemetry into a central SIEM and pivot on Chrome renderer crashes per host over time.
- Track Chrome auto-update success rates and alert when fleet versions drift from the current stable channel.
- Monitor for post-exploitation behavior such as credential access, persistence creation, or PowerShell launches originating from the Chrome process tree.
How to Mitigate CVE-2020-15994
Immediate Actions Required
- Update Chrome and Chrome for Android to version 86.0.4240.99 or later on every managed device.
- Restart Chrome after the update so the patched V8 binary is loaded into memory.
- Verify auto-update services (GoogleUpdate.exe on Windows, the Play Store update channel on Android) are enabled and reachable.
Patch Information
Google shipped the fix in the Chrome stable channel announcement on October 31, 2020. Details are available in the Google Chrome Android Update advisory. Desktop Chrome users receive the corrected V8 component through the standard stable channel update to 86.0.4240.99.
Workarounds
- Restrict JavaScript execution on untrusted sites using enterprise policy DefaultJavaScriptSetting until the patch is deployed.
- Route browser traffic through a filtering proxy that blocks newly registered and low-reputation domains.
- Deploy site isolation enforcement (SitePerProcess) so renderer compromise is contained to a single origin.
# Verify the installed Chrome version on Windows endpoints
reg query "HKLM\SOFTWARE\WOW6432Node\Google\Update\Clients\{8A69D345-D564-463C-AFF1-A69D9E530F96}" /v pv
# Enforce site isolation and disable JavaScript on untrusted zones via policy (Windows)
reg add "HKLM\SOFTWARE\Policies\Google\Chrome" /v SitePerProcess /t REG_DWORD /d 1 /f
reg add "HKLM\SOFTWARE\Policies\Google\Chrome" /v DefaultJavaScriptSetting /t REG_DWORD /d 2 /f
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
