The SentinelOne Annual Threat Report - A Defenders Guide from the FrontlinesThe SentinelOne Annual Threat ReportGet the Report
Experiencing a Breach?Blog
Get StartedContact Us
SentinelOne
  • Platform
    Platform Overview
    • Singularity Platform
      Welcome to Integrated Enterprise Security
    • AI for Security
      Leading the Way in AI-Powered Security Solutions
    • Securing AI
      Accelerate AI Adoption with Secure AI Tools, Apps, and Agents.
    • How It Works
      The Singularity XDR Difference
    • Singularity Marketplace
      One-Click Integrations to Unlock the Power of XDR
    • Pricing & Packaging
      Comparisons and Guidance at a Glance
    Data & AI
    • Purple AI
      Accelerate SecOps with Generative AI
    • Singularity Hyperautomation
      Easily Automate Security Processes
    • AI-SIEM
      The AI SIEM for the Autonomous SOC
    • AI Data Pipelines
      Security Data Pipeline for AI SIEM and Data Optimization
    • Singularity Data Lake
      AI-Powered, Unified Data Lake
    • Singularity Data Lake for Log Analytics
      Seamlessly Ingest Data from On-Prem, Cloud or Hybrid Environments
    Endpoint Security
    • Singularity Endpoint
      Autonomous Prevention, Detection, and Response
    • Singularity XDR
      Native & Open Protection, Detection, and Response
    • Singularity RemoteOps Forensics
      Orchestrate Forensics at Scale
    • Singularity Threat Intelligence
      Comprehensive Adversary Intelligence
    • Singularity Vulnerability Management
      Application & OS Vulnerability Management
    • Singularity Identity
      Identity Threat Detection and Response
    Cloud Security
    • Singularity Cloud Security
      Block Attacks with an AI-Powered CNAPP
    • Singularity Cloud Native Security
      Secure Cloud and Development Resources
    • Singularity Cloud Workload Security
      Real-Time Cloud Workload Protection Platform
    • Singularity Cloud Data Security
      AI-Powered Threat Detection for Cloud Storage
    • Singularity Cloud Security Posture Management
      Detect and Remediate Cloud Misconfigurations
    Securing AI
    • Prompt Security
      Secure AI Tools Across Your Enterprise
  • Why SentinelOne?
    Why SentinelOne?
    • Why SentinelOne?
      Cybersecurity Built for What’s Next
    • Our Customers
      Trusted by the World’s Leading Enterprises
    • Industry Recognition
      Tested and Proven by the Experts
    • About Us
      The Industry Leader in Autonomous Cybersecurity
    Compare SentinelOne
    • Arctic Wolf
    • Broadcom
    • CrowdStrike
    • Cybereason
    • Microsoft
    • Palo Alto Networks
    • Sophos
    • Splunk
    • Trellix
    • Trend Micro
    • Wiz
    Verticals
    • Energy
    • Federal Government
    • Finance
    • Healthcare
    • Higher Education
    • K-12 Education
    • Manufacturing
    • Retail
    • State and Local Government
  • Services
    Managed Services
    • Managed Services Overview
      Wayfinder Threat Detection & Response
    • Threat Hunting
      World-Class Expertise and Threat Intelligence
    • Managed Detection & Response
      24/7/365 Expert MDR Across Your Entire Environment
    • Incident Readiness & Response
      DFIR, Breach Readiness, & Compromise Assessments
    Support, Deployment, & Health
    • Technical Account Management
      Customer Success with Personalized Service
    • SentinelOne GO
      Guided Onboarding & Deployment Advisory
    • SentinelOne University
      Live and On-Demand Training
    • Services Overview
      Comprehensive Solutions for Seamless Security Operations
    • SentinelOne Community
      Community Login
  • Partners
    Our Network
    • MSSP Partners
      Succeed Faster with SentinelOne
    • Singularity Marketplace
      Extend the Power of S1 Technology
    • Cyber Risk Partners
      Enlist Pro Response and Advisory Teams
    • Technology Alliances
      Integrated, Enterprise-Scale Solutions
    • SentinelOne for AWS
      Hosted in AWS Regions Around the World
    • Channel Partners
      Deliver the Right Solutions, Together
    • SentinelOne for Google Cloud
      Unified, Autonomous Security Giving Defenders the Advantage at Global Scale
    • Partner Locator
      Your Go-to Source for Our Top Partners in Your Region
    Partner Portal→
  • Resources
    Resource Center
    • Case Studies
    • Data Sheets
    • eBooks
    • Reports
    • Videos
    • Webinars
    • Whitepapers
    • Events
    View All Resources→
    Blog
    • Feature Spotlight
    • For CISO/CIO
    • From the Front Lines
    • Identity
    • Cloud
    • macOS
    • SentinelOne Blog
    Blog→
    Tech Resources
    • SentinelLABS
    • Ransomware Anthology
    • Cybersecurity 101
  • About
    About SentinelOne
    • About SentinelOne
      The Industry Leader in Cybersecurity
    • Investor Relations
      Financial Information & Events
    • SentinelLABS
      Threat Research for the Modern Threat Hunter
    • Careers
      The Latest Job Opportunities
    • Press & News
      Company Announcements
    • Cybersecurity Blog
      The Latest Cybersecurity Threats, News, & More
    • FAQ
      Get Answers to Our Most Frequently Asked Questions
    • DataSet
      The Live Data Platform
    • S Foundation
      Securing a Safer Future for All
    • S Ventures
      Investing in the Next Generation of Security, Data and AI
  • Pricing
Get StartedContact Us
CVE Vulnerability Database
Vulnerability Database/CVE-2025-13020

CVE-2025-13020: Mozilla Firefox Use-After-Free Vulnerability

CVE-2025-13020 is a use-after-free vulnerability in Mozilla Firefox's WebRTC Audio/Video component that could allow attackers to exploit memory corruption. This article covers technical details, affected versions, and patches.

Published: April 29, 2026

CVE-2025-13020 Overview

CVE-2025-13020 is a use-after-free vulnerability in the WebRTC Audio/Video component of Mozilla Firefox, Firefox ESR, and Thunderbird. This memory corruption flaw occurs when the browser improperly handles memory associated with WebRTC audio and video processing, potentially allowing an attacker to execute arbitrary code within the context of the user's browser session.

Critical Impact

This use-after-free vulnerability in WebRTC could allow remote attackers to achieve code execution through specially crafted web content, potentially leading to complete compromise of user confidentiality, integrity, and system availability.

Affected Products

  • Mozilla Firefox versions prior to 145
  • Mozilla Firefox ESR versions prior to 140.5
  • Mozilla Thunderbird versions prior to 145 and 140.5

Discovery Timeline

  • 2025-11-11 - CVE-2025-13020 published to NVD
  • 2026-04-13 - Last updated in NVD database

Technical Details for CVE-2025-13020

Vulnerability Analysis

This vulnerability is classified as CWE-416 (Use After Free), a memory corruption issue that occurs when a program continues to reference memory after it has been freed. In the context of Mozilla's WebRTC implementation, the Audio/Video component contains a flaw where freed memory associated with media stream processing can be accessed again, leading to undefined behavior.

The vulnerability requires user interaction to exploit—specifically, a user must visit a malicious webpage or be exposed to crafted WebRTC content. Once triggered, an attacker could potentially hijack program execution flow, leading to arbitrary code execution with the privileges of the browser process. This could result in complete compromise of confidentiality, integrity, and availability of the affected system.

Root Cause

The root cause of CVE-2025-13020 lies in improper memory lifecycle management within the WebRTC Audio/Video component. When certain audio or video stream objects are deallocated, references to these objects may persist in other parts of the codebase. Subsequent operations that attempt to access these dangling pointers result in use-after-free conditions.

This type of vulnerability typically arises from complex object lifetimes in multimedia processing code, where asynchronous operations and callback mechanisms can lead to scenarios where memory is freed while still being referenced elsewhere.

Attack Vector

The attack vector for this vulnerability is network-based, requiring no privileges but necessitating user interaction. An attacker could exploit this vulnerability by:

  1. Crafting a malicious webpage containing WebRTC content designed to trigger the use-after-free condition
  2. Luring a victim to visit the webpage through phishing or social engineering
  3. The malicious WebRTC content triggers improper memory handling in the Audio/Video component
  4. Memory corruption occurs, potentially allowing the attacker to execute arbitrary code

The vulnerability mechanism involves timing-sensitive operations in WebRTC stream handling. Technical details are available in Mozilla Bug Report #1995686 and the associated security advisories.

Detection Methods for CVE-2025-13020

Indicators of Compromise

  • Unexpected browser crashes or instability when visiting websites with WebRTC functionality
  • Anomalous memory access patterns in Firefox or Thunderbird processes
  • Suspicious network connections initiated from browser processes following WebRTC sessions
  • Unexpected child process spawning from browser application contexts

Detection Strategies

  • Monitor for exploitation attempts by deploying endpoint detection solutions capable of identifying memory corruption exploitation techniques
  • Implement browser-level telemetry to detect anomalous WebRTC behavior patterns
  • Deploy network monitoring to identify connections to known malicious domains serving exploit content
  • Use SentinelOne Singularity to detect post-exploitation behaviors such as unauthorized code execution from browser processes

Monitoring Recommendations

  • Enable crash reporting in Mozilla products to identify potential exploitation attempts
  • Monitor system logs for browser process anomalies, including unexpected memory access violations
  • Implement web content filtering to block access to known malicious sites
  • Track browser version deployments across the organization to ensure vulnerable versions are identified

How to Mitigate CVE-2025-13020

Immediate Actions Required

  • Update Mozilla Firefox to version 145 or later immediately
  • Update Mozilla Firefox ESR to version 140.5 or later
  • Update Mozilla Thunderbird to version 145 or 140.5 or later
  • Consider temporarily disabling WebRTC functionality in environments where updates cannot be immediately applied

Patch Information

Mozilla has released security patches addressing this vulnerability in the following versions:

  • Firefox 145 - Mozilla Security Advisory MFSA-2025-87
  • Firefox ESR 140.5 - Mozilla Security Advisory MFSA-2025-88
  • Thunderbird 145 - Mozilla Security Advisory MFSA-2025-90
  • Thunderbird 140.5 - Mozilla Security Advisory MFSA-2025-91

Organizations should prioritize deploying these updates through their software management infrastructure.

Workarounds

  • Disable WebRTC in Firefox by setting media.peerconnection.enabled to false in about:config
  • Use browser policies to restrict access to WebRTC functionality in enterprise environments
  • Implement network-level controls to block WebRTC traffic if the feature is not required
  • Deploy web content filtering to prevent access to potentially malicious sites until patching is complete
bash
# Firefox policy configuration to disable WebRTC (policies.json)
# Place in Firefox installation directory under distribution/policies.json
{
  "policies": {
    "Preferences": {
      "media.peerconnection.enabled": {
        "Value": false,
        "Status": "locked"
      }
    }
  }
}

Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.

  • Vulnerability Details
  • TypeUse After Free

  • Vendor/TechMozilla Firefox

  • SeverityHIGH

  • CVSS Score8.8

  • EPSS Probability0.06%

  • Known ExploitedNo
  • CVSS Vector
  • CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
  • Impact Assessment
  • ConfidentialityLow
  • IntegrityHigh
  • AvailabilityHigh
  • CWE References
  • CWE-416
  • Technical References
  • Mozilla Bug Report #1995686

  • Mozilla Security Advisory MFSA-2025-90

  • Mozilla Security Advisory MFSA-2025-91
  • Vendor Resources
  • Mozilla Security Advisory MFSA-2025-87

  • Mozilla Security Advisory MFSA-2025-88
  • Related CVEs
  • CVE-2026-6757: Mozilla Firefox Use-After-Free Vulnerability

  • CVE-2026-6751: Mozilla Firefox Use-After-Free Vulnerability

  • CVE-2026-6759: Mozilla Firefox Use-After-Free Vulnerability

  • CVE-2026-6778: Mozilla Firefox Use-After-Free Vulnerability
Default Legacy - Prefooter | Experience the World’s Most Advanced Cybersecurity Platform

Experience the World’s Most Advanced Cybersecurity Platform

See how our intelligent, autonomous cybersecurity platform can protect your organization now and into the future.

Try SentinelOne
  • Get Started
  • Get a Demo
  • Product Tour
  • Why SentinelOne
  • Pricing & Packaging
  • FAQ
  • Contact
  • Contact Us
  • Customer Support
  • SentinelOne Status
  • Language
  • Platform
  • Singularity Platform
  • Singularity Endpoint
  • Singularity Cloud
  • Singularity AI-SIEM
  • Singularity Identity
  • Singularity Marketplace
  • Purple AI
  • Services
  • Wayfinder TDR
  • SentinelOne GO
  • Technical Account Management
  • Support Services
  • Verticals
  • Energy
  • Federal Government
  • Finance
  • Healthcare
  • Higher Education
  • K-12 Education
  • Manufacturing
  • Retail
  • State and Local Government
  • Cybersecurity for SMB
  • Resources
  • Blog
  • Labs
  • Case Studies
  • Videos
  • Product Tours
  • Events
  • Cybersecurity 101
  • eBooks
  • Webinars
  • Whitepapers
  • Press
  • News
  • Ransomware Anthology
  • Company
  • About Us
  • Our Customers
  • Careers
  • Partners
  • Legal & Compliance
  • Security & Compliance
  • Investor Relations
  • S Foundation
  • S Ventures

©2026 SentinelOne, All Rights Reserved.

Privacy Notice Terms of Use

English