CVE-2022-1802

What it actually does

Prototype pollution allows an attacker to corrupt methods on the Array object in JavaScript, resulting in execution of attacker-controlled code within a privileged browser context.

Why it matters to the business

Successful exploitation can lead to full browser compromise, enabling theft of credentials, session data, or installation of malware on user systems, increasing risk of data breaches and operational disruption for organizations relying on affected browsers.

How an attack unfolds

An attacker crafts a malicious webpage or script that triggers prototype pollution to overwrite Array methods, then leverages the corrupted methods to inject and execute arbitrary JavaScript in a privileged context such as chrome or extension privileges.

How to fix it

Upgrade Mozilla Firefox to 100.0.2 or later, Firefox ESR to 91.9.1 or later, Firefox for Android to 100.3.0 or later, and Thunderbird to 91.9.1 or later. Apply updates immediately across all endpoints and disable JavaScript where feasible as a temporary mitigation.

How to confirm the fix worked

Verify browser versions match or exceed the fixed releases listed in vendor advisories; test by confirming absence of prototype pollution effects in JavaScript execution contexts using standard browser developer tools or automated version checks.

Typical attack path

1. Deliver malicious JavaScript via a crafted webpage or third-party script
2. Trigger prototype pollution to corrupt Array object methods
3. Abuse the corrupted methods to escape sandbox and execute code in privileged context
4. Perform actions such as credential theft or persistence within the browser

How to detect it

Review browser process logs, extension activity, and network requests for signs of unexpected privileged JavaScript execution; correlate with web proxy logs showing visits to suspicious domains shortly before anomalous behavior.

What your security team should do

• Prioritize patching all affected Mozilla products within 48 hours due to high CVSS and moderate EPSS
• Enable automatic updates for Firefox, ESR, Thunderbird, and Android browsers enterprise-wide
• Monitor for unusual JavaScript execution patterns in browser logs and restrict third-party scripts
• Conduct inventory of all Mozilla-based deployments to ensure complete coverage