CVE-2024-10459: Mozilla Firefox Use-After-Free Vulnerability

CVE-2024-10459 Overview

CVE-2024-10459 is a use-after-free memory corruption vulnerability affecting Mozilla Firefox and Thunderbird products. The vulnerability is triggered when accessibility features are enabled in the browser, potentially allowing an attacker to cause a crash that could be exploited for further malicious purposes. This type of memory safety issue occurs when the application attempts to access memory that has already been freed, leading to undefined behavior that attackers may leverage.

Critical Impact

Use-after-free vulnerabilities can lead to denial of service conditions and potentially arbitrary code execution if successfully exploited.

Affected Products

• Mozilla Firefox versions prior to 132
• Mozilla Firefox ESR versions prior to 128.4 and 115.17
• Mozilla Thunderbird versions prior to 128.4 and 132

Discovery Timeline

• 2024-10-29 - CVE-2024-10459 published to NVD
• 2025-11-03 - Last updated in NVD database

Technical Details for CVE-2024-10459

Vulnerability Analysis

This vulnerability is classified as CWE-416 (Use After Free), a memory corruption issue that occurs when a program continues to use a pointer after the memory it references has been deallocated. In the context of Mozilla Firefox and Thunderbird, the vulnerability manifests specifically when accessibility features are enabled. The accessibility subsystem in modern browsers provides interfaces for screen readers and other assistive technologies, and the complexity of maintaining memory state across these interfaces can introduce memory safety bugs.

When exploited, the application attempts to access freed memory during accessibility-related operations. This can result in a crash condition, and depending on the memory state at the time of exploitation, could potentially be leveraged for more severe attacks such as code execution. The attack can be initiated remotely over a network without requiring authentication or user interaction.

Root Cause

The root cause is improper memory management within the accessibility component of Mozilla Firefox and Thunderbird. When certain accessibility features are active, the application fails to properly track the lifecycle of memory objects, leading to a situation where a reference to freed memory is retained and subsequently dereferenced. This is tracked in Mozilla Bug Report #1919087.

Attack Vector

The vulnerability can be exploited remotely over a network connection. An attacker could craft malicious web content that, when loaded by a victim with accessibility features enabled, triggers the use-after-free condition. The attack does not require any special privileges or direct user interaction beyond visiting the malicious page. The vulnerability specifically requires that accessibility features be enabled in the target browser, which limits the attack surface to users who have these features active.

The exploitation mechanism involves triggering specific accessibility API calls that result in the application attempting to access previously freed memory structures. Without verified proof-of-concept code available, the exact technical steps for exploitation are documented in Mozilla's internal security tracking systems.

Detection Methods for CVE-2024-10459

Indicators of Compromise

• Unexpected browser or email client crashes when visiting websites with accessibility features enabled
• Application crash reports referencing memory access violations in accessibility-related components
• Crash dump analysis revealing use-after-free patterns in firefox.exe or thunderbird.exe processes
• System logs indicating abnormal termination of Mozilla products with accessibility modules loaded

Detection Strategies

• Monitor for abnormal crash rates in Mozilla Firefox and Thunderbird across the organization
• Implement endpoint detection rules for process crashes with memory corruption signatures
• Deploy SentinelOne behavioral analysis to detect exploitation attempts targeting browser memory corruption
• Review application crash reports for patterns consistent with use-after-free exploitation

Monitoring Recommendations

• Enable enhanced logging for browser crashes and correlate with network activity
• Implement browser version inventory tracking to identify vulnerable installations
• Configure security tools to alert on exploitation attempts targeting browser vulnerabilities
• Monitor for unusual process behavior from Firefox and Thunderbird, particularly memory access anomalies

How to Mitigate CVE-2024-10459

Immediate Actions Required

• Update Mozilla Firefox to version 132 or later immediately
• Update Mozilla Firefox ESR to version 128.4 or 115.17 or later
• Update Mozilla Thunderbird to version 128.4 or 132 or later
• Prioritize updates for systems where accessibility features are commonly used

Patch Information

Mozilla has released security patches addressing this vulnerability. The following versions contain the fix:

• Firefox 132 - Mozilla Security Advisory MFSA-2024-55
• Firefox ESR 128.4 - Mozilla Security Advisory MFSA-2024-56
• Firefox ESR 115.17 - Mozilla Security Advisory MFSA-2024-57
• Thunderbird 128.4 - Mozilla Security Advisory MFSA-2024-58
• Thunderbird 132 - Mozilla Security Advisory MFSA-2024-59

Debian Linux users should also apply patches per Debian LTS Announcement #34 and Debian LTS Announcement #01.

Workarounds

• As a temporary measure, disable accessibility features if they are not required for users
• Implement network-level filtering to block known malicious content targeting browser vulnerabilities
• Consider using alternative browsers until patches can be applied
• Restrict browsing to trusted sites for users who cannot immediately update

# Check Firefox version on Linux systems
firefox --version

# Check Thunderbird version on Linux systems
thunderbird --version

# Update Firefox on Debian/Ubuntu
sudo apt update && sudo apt install firefox

# Update Thunderbird on Debian/Ubuntu
sudo apt update && sudo apt install thunderbird