CVE-2025-14323: Mozilla Firefox Privilege Escalation Flaw

CVE-2025-14323 Overview

CVE-2025-14323 is a privilege escalation vulnerability affecting the DOM Notifications component in Mozilla Firefox and Thunderbird. This security flaw allows attackers to escalate privileges through the browser's notification handling mechanism, potentially enabling unauthorized actions with elevated permissions within the affected applications.

Critical Impact

Successful exploitation could allow an attacker to escalate privileges within the browser context, potentially leading to unauthorized access to sensitive data, arbitrary code execution, or complete compromise of the user's browser session.

Affected Products

• Mozilla Firefox (versions prior to 146)
• Mozilla Firefox ESR (versions prior to 115.31 and 140.6)
• Mozilla Thunderbird (versions prior to 146 and 140.6)

Discovery Timeline

• December 9, 2025 - CVE-2025-14323 published to NVD
• April 13, 2026 - Last updated in NVD database

Technical Details for CVE-2025-14323

Vulnerability Analysis

This privilege escalation vulnerability resides within the DOM Notifications component of Mozilla's browser engine. The Notifications API allows web pages to display system-level notifications to users, and improper handling within this component creates an opportunity for privilege escalation.

The vulnerability can be triggered when a user interacts with malicious web content that exploits the flaw in notification handling. Upon successful exploitation, an attacker could execute actions with elevated privileges that would normally be restricted, potentially bypassing security boundaries enforced by the browser's sandbox.

The attack requires user interaction, meaning a victim must visit a malicious website or be redirected to attacker-controlled content. However, once triggered, the impact is significant as it affects confidentiality, integrity, and availability of the system.

Root Cause

The root cause stems from improper privilege handling within the DOM Notifications component. When processing notification-related operations, the affected code fails to properly validate or restrict the privilege context, allowing an attacker to escalate from web content privileges to a higher privilege level within the browser process.

Attack Vector

The attack vector is network-based, requiring the victim to access attacker-controlled web content. The exploitation flow typically involves:

1. Victim navigates to or is redirected to a malicious webpage
2. The malicious page invokes the Notifications API in a crafted manner
3. The vulnerability in the DOM Notifications component is triggered
4. Privilege escalation occurs within the browser context
5. Attacker gains elevated access to perform unauthorized actions

The vulnerability mechanism exploits the notification handling process within the browser's DOM implementation. For detailed technical information, refer to the Mozilla Bug Report #1996555 and the associated security advisories.

Detection Methods for CVE-2025-14323

Indicators of Compromise

• Unusual notification permission requests or behaviors from untrusted websites
• Unexpected browser process activity or elevated privilege operations
• Anomalous JavaScript execution patterns related to Notification API calls
• Browser crash logs indicating issues within notification components

Detection Strategies

• Monitor for suspicious web content attempting to abuse Notification API functionality
• Implement network-based detection for known malicious payloads targeting this vulnerability
• Deploy endpoint detection rules to identify privilege escalation attempts within browser processes
• Review browser console logs for errors or warnings related to notification handling

Monitoring Recommendations

• Enable detailed browser logging to capture notification-related activities
• Monitor endpoint telemetry for signs of browser exploitation attempts
• Track browser version inventory across the organization to identify vulnerable installations
• Implement web filtering to block access to known malicious domains

How to Mitigate CVE-2025-14323

Immediate Actions Required

• Update Mozilla Firefox to version 146 or later immediately
• Update Mozilla Firefox ESR to version 115.31 or 140.6 or later
• Update Mozilla Thunderbird to version 146 or 140.6 or later
• Review and restrict notification permissions for untrusted sites
• Consider disabling browser notifications temporarily until patches are applied

Patch Information

Mozilla has released security patches addressing this vulnerability across multiple product versions. The fix is included in:

• Firefox 146
• Firefox ESR 115.31
• Firefox ESR 140.6
• Thunderbird 146
• Thunderbird 140.6

Organizations should prioritize patching based on their deployment. Detailed patch information is available in the following Mozilla Security Advisories:

• MFSA-2025-92
• MFSA-2025-93
• MFSA-2025-94
• MFSA-2025-95
• MFSA-2025-96

Workarounds

• Disable browser notifications system-wide via group policy or browser configuration
• Block notification permission prompts using browser security policies
• Implement strict Content Security Policy (CSP) headers on internal web applications
• Use web filtering to prevent access to potentially malicious sites until patches are deployed

# Firefox configuration to disable notifications via policies.json
# Location: /etc/firefox/policies/policies.json (Linux) or distribution folder (Windows)
{
  "policies": {
    "Permissions": {
      "Notifications": {
        "BlockNewRequests": true,
        "Locked": true
      }
    }
  }
}