CVE-2026-10702: Firefox for Android JIT Type Confusion Vulnerability

Lookout Coverage and Recommendation for Admins

Lookout is releasing security coverage for CVE-2026-10702 affecting Mozilla Firefox for Android on Jul 23, 2026. Once coverage is deployed, the platform will automatically generate alerts and initiate workflows in accordance with each administrator's configured risk thresholds, response policies, and escalation procedures.

To ensure devices are protected, Lookout administrators should take the following actions within the Lookout console:

Enable the Application Vulnerability policy to detect vulnerable Firefox versions (version 151.0.3 and below). Given the public disclosure of a working exploit chain, Lookout recommends setting the severity to High and considering blocking access to work data until affected browsers are updated.
Remediate all devices running Mozilla Firefox for Android versions prior to 151.0.3.
Enable Lookout Phishing & Content Protection (PCP) to protect mobile users from phishing campaigns and malicious websites designed to exploit browser vulnerabilities, steal credentials, or deliver malicious payloads.

Overview

A security researcher recently disclosed a vulnerability in Mozilla Firefox's SpiderMonkey JavaScript engine affecting Firefox for Android. Tracked as CVE-2026-10702, the vulnerability is a type confusion flaw (CWE-843) stemming from a Just-In-Time (JIT) miscompilation issue in the IonMonkey/Warp compiler pipeline. The vulnerability has been incorporated into a publicized one-click Android exploit chain by a security startup, elevating its risk profile beyond its base severity.

Successful exploitation could allow an attacker to corrupt content-process memory within the browser, potentially serving as a stepping stone toward arbitrary code execution when combined with a sandbox escape. The vulnerability has been assigned a CVSS score of up to 7.5 (High). Mozilla has released a patch in Firefox for Android version 151.0.3 and later. Devices running versions below these thresholds are vulnerable and should be updated immediately.

While active exploitation in the wild has not been confirmed at this time, the public disclosure of a working one-click Android exploit chain incorporating this vulnerability means enterprise organizations are strongly encouraged to remediate promptly.

Lookout Analysis

This vulnerability poses a high risk due to its inclusion in a publicized Android exploit chain. Successful exploitation could expose sensitive information accessible to the browser, including session cookies, authentication tokens, enterprise credentials, and personally identifiable information (PII). Depending on the user's context and privileges, exploitation may also enable unauthorized actions on behalf of the user.

The exploitation of CVE-2026-10702 generally follows these stages:

Luring: The user is directed to a malicious or specially crafted webpage containing attacker-controlled JavaScript.
Triggering: The browser processes the JavaScript content, invoking the vulnerable SpiderMonkey JIT compiler.
Type Confusion: A JIT miscompilation causes the compiler to emit machine code inconsistent with actual runtime variable types, resulting in type confusion.
Memory Corruption: The type confusion condition leads to corruption of content-process memory within the browser.
Exploitation: As part of a one-click exploit chain, the attacker leverages the memory corruption to achieve code execution, potentially combined with a sandbox escape.
Post-Exploitation: The attacker may conduct credential theft, session hijacking, malware delivery, or other malicious activities.