CVE-2025-10535: Firefox Android Info Disclosure Flaw

CVE-2025-10535 Overview

CVE-2025-10535 is an information disclosure vulnerability affecting the Privacy component in Firefox for Android. This security flaw enables attackers to bypass privacy mitigations implemented in the browser, potentially exposing sensitive user information. The vulnerability was addressed in Firefox version 143.

Critical Impact

This vulnerability allows attackers to bypass privacy protections in Firefox for Android, potentially leading to unauthorized disclosure of sensitive user data and undermining the browser's security controls.

Affected Products

• Mozilla Firefox for Android (versions prior to 143)

Discovery Timeline

• 2025-09-16 - CVE-2025-10535 published to NVD
• 2026-04-13 - Last updated in NVD database

Technical Details for CVE-2025-10535

Vulnerability Analysis

This vulnerability affects the Privacy component within Firefox for Android, a critical security feature designed to protect user data and enforce privacy boundaries during browsing sessions. The flaw enables both information disclosure and mitigation bypass, indicating that existing privacy protections can be circumvented by an attacker.

The vulnerability is accessible via network-based attack vectors without requiring user interaction or special privileges. This characteristic makes it particularly concerning for mobile users who may be connected to untrusted networks. The impact is primarily focused on integrity, suggesting that attackers can manipulate or bypass security controls rather than directly extract data.

Root Cause

The root cause relates to CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor). The Privacy component in Firefox for Android fails to properly protect sensitive information, allowing unauthorized access through a mitigation bypass. This indicates an implementation flaw in how privacy controls are enforced within the mobile browser's architecture.

Attack Vector

The attack vector is network-based with low complexity, meaning an attacker can exploit this vulnerability remotely without requiring authentication or user interaction. The attacker may leverage this flaw to bypass privacy mitigations that Firefox for Android employs to protect user data during browsing sessions. This could potentially be exploited through malicious web content or network-level interception.

For technical details regarding the specific exploitation mechanism, refer to the Mozilla Bug Report #1979918 and the Mozilla Security Advisory MFSA-2025-73.

Detection Methods for CVE-2025-10535

Indicators of Compromise

• Unusual data transmissions from Firefox for Android to unknown destinations
• Unexpected behavior in privacy-related browser features or settings
• Evidence of privacy controls being disabled or bypassed without user action
• Anomalous network traffic patterns during Firefox browsing sessions

Detection Strategies

• Monitor for attempts to access or manipulate Firefox for Android privacy settings through external vectors
• Implement network traffic analysis to detect suspicious data exfiltration patterns from mobile devices
• Review application logs for evidence of privacy component manipulation or unexpected state changes
• Deploy mobile threat detection solutions capable of identifying browser-based exploits

Monitoring Recommendations

• Enable enhanced logging for Firefox for Android browser activity on managed devices
• Implement network-level monitoring for mobile devices accessing corporate resources
• Configure mobile device management (MDM) solutions to alert on outdated Firefox versions
• Establish baseline browser behavior to detect anomalies indicative of exploitation

How to Mitigate CVE-2025-10535

Immediate Actions Required

• Update Firefox for Android to version 143 or later immediately
• Review recent browsing activity for signs of unauthorized data access
• Enable automatic updates for Firefox for Android to ensure timely security patches
• Consider using alternative browsers until the update can be applied if immediate patching is not possible

Patch Information

Mozilla has addressed this vulnerability in Firefox version 143. Users should update through the Google Play Store or their device's app store. The official security advisory is available at the Mozilla Security Advisory MFSA-2025-73.

Workarounds

• Restrict Firefox for Android usage on untrusted networks until patched
• Enable enhanced tracking protection and privacy features within Firefox settings as an additional layer
• Use a VPN when browsing with vulnerable Firefox versions to add network-level protection
• Consider temporary use of Firefox Focus or other privacy-focused browsers until the update is applied

# Verify Firefox for Android version via ADB
adb shell dumpsys package org.mozilla.firefox | grep versionName
# Expected output for patched version: versionName=143.x or higher