CVE-2026-2794: Mozilla Firefox Information Disclosure

CVE-2026-2794 Overview

CVE-2026-2794 is an information disclosure vulnerability affecting Mozilla Firefox and Firefox Focus for Android, classified as CWE-908 (Use of Uninitialized Resource). The vulnerability allows attackers to exploit uninitialized memory conditions to potentially access sensitive data that should otherwise be protected.

Critical Impact

Attackers can leverage this uninitialized memory vulnerability to disclose sensitive information from Firefox processes on Android devices without requiring user interaction or special privileges.

Affected Products

• Mozilla Firefox versions prior to 148
• Firefox Focus for Android (versions prior to 148)

Discovery Timeline

• 2026-02-24 - CVE-2026-2794 published to NVD
• 2026-02-26 - Last updated in NVD database

Technical Details for CVE-2026-2794

Vulnerability Analysis

This vulnerability stems from the use of uninitialized memory within Firefox and Firefox Focus for Android. When memory is allocated but not properly initialized before use, it may contain residual data from previous operations. An attacker exploiting this flaw could read this uninitialized memory to extract sensitive information such as session tokens, user credentials, or other confidential data processed by the browser.

The network-based attack vector means this vulnerability can be triggered remotely, potentially through malicious web content that causes the browser to access uninitialized memory regions. The exploitation requires no user interaction and no special privileges, making it particularly concerning for mobile users browsing untrusted websites.

Root Cause

The root cause is classified as CWE-908: Use of Uninitialized Resource. This occurs when the Firefox codebase allocates memory buffers that are subsequently read without first being properly initialized or zeroed out. On Android platforms, this can expose memory contents from previous browser operations or system processes.

Attack Vector

The vulnerability is exploitable over the network, requiring no authentication or user interaction. An attacker could craft malicious web content designed to trigger the uninitialized memory read condition. When a victim visits the malicious page using an affected Firefox version on Android, the browser may leak sensitive memory contents back to the attacker-controlled server.

The attack leverages the browser's memory handling routines where allocated buffers are not properly sanitized before use. This could occur in rendering components, JavaScript engines, or network handling code paths specific to the Android implementation.

Detection Methods for CVE-2026-2794

Indicators of Compromise

• Unusual network traffic patterns from Firefox processes sending unexpected data to external servers
• Memory access anomalies detected in Firefox application logs on Android devices
• Crash reports related to memory access violations in Firefox for Android

Detection Strategies

• Monitor for Firefox for Android versions below 148 in enterprise mobile device management (MDM) systems
• Implement network traffic analysis to detect potential data exfiltration from browser processes
• Review application logs for signs of memory-related errors or crashes in Firefox

Monitoring Recommendations

• Deploy endpoint detection and response (EDR) solutions that monitor mobile browser behavior
• Enable verbose logging for Firefox on managed Android devices to capture memory-related events
• Utilize network security monitoring to identify suspicious outbound connections from Firefox processes

How to Mitigate CVE-2026-2794

Immediate Actions Required

• Update Mozilla Firefox to version 148 or later on all Android devices immediately
• Update Firefox Focus for Android to the latest available version
• Review enterprise MDM policies to enforce browser version requirements
• Consider temporarily restricting access to untrusted websites until patches are applied

Patch Information

Mozilla has addressed this vulnerability in Firefox version 148. Organizations should prioritize updating all Firefox and Firefox Focus installations on Android devices. The official security advisory is available at Mozilla Security Advisory MFSA-2026-13, and technical details can be found in Mozilla Bug Report #2008365.

Workarounds

• Limit Firefox usage on Android devices to trusted websites until patching is complete
• Consider using alternative browsers temporarily on Android if immediate patching is not feasible
• Implement network-level filtering to block access to known malicious domains
• Enable enhanced tracking protection features in Firefox to reduce exposure to potentially malicious content

# Verify Firefox version on Android via ADB
adb shell dumpsys package org.mozilla.firefox | grep versionName
# Expected output should show version 148 or higher