CVE-2024-5702: Mozilla Firefox DOS Vulnerability

CVE-2024-5702 Overview

CVE-2024-5702 is a memory corruption vulnerability in the networking stack of Mozilla Firefox, Firefox ESR, and Thunderbird. The flaw, classified as a use-after-free condition [CWE-416], could lead to a potentially exploitable crash when processing network traffic. The vulnerability affects Firefox versions prior to 125, Firefox ESR prior to 115.12, and Thunderbird prior to 115.12. A remote attacker can trigger the condition over the network without authentication or user interaction.

Critical Impact
Remote attackers can trigger memory corruption in the browser networking stack, causing application crashes and potentially enabling further exploitation.

Affected Products

Mozilla Firefox versions earlier than 125
Mozilla Firefox ESR versions earlier than 115.12
Mozilla Thunderbird versions earlier than 115.12

Discovery Timeline

2024-06-11 - CVE-2024-5702 published to the National Vulnerability Database
2024-06-11 - Mozilla publishes security advisories MFSA-2024-18, MFSA-2024-26, and MFSA-2024-28
2025-04-04 - Last updated in NVD database

Technical Details for CVE-2024-5702

Vulnerability Analysis

The vulnerability resides in the networking stack shared across Firefox, Firefox ESR, and Thunderbird. Mozilla classified the defect as a memory corruption condition that produces a potentially exploitable crash. The Common Weakness Enumeration entry [CWE-416] identifies this issue as a use-after-free, meaning the code references heap memory after it has been released.

Use-after-free conditions in networking code are particularly concerning because the trigger surface includes any traffic the client processes. The networking stack handles untrusted data from arbitrary remote servers, expanding the attack surface beyond user-initiated actions. According to Mozilla's advisory, the corruption was reachable in a manner consistent with remote exploitation primitives.

Root Cause

The root cause is improper lifetime management of an object referenced by the networking stack. When the underlying memory is freed but a dangling pointer remains, subsequent operations dereference invalid memory. Mozilla bug report #1193389 tracks the long-standing issue addressed by this fix. The remediation modifies object ownership and reference handling to ensure freed memory is no longer accessed.

Attack Vector

An attacker delivers crafted network responses to a vulnerable client. Because the flaw lives in the networking stack itself, exploitation does not require interaction with web content APIs beyond initiating a connection. The attacker requires no privileges and no user interaction beyond having the client process the malicious traffic. A successful trigger produces a crash that could be leveraged for code execution depending on heap state and mitigations in place. Refer to the Mozilla Security Advisory MFSA-2024-26 for the official technical description.

Detection Methods for CVE-2024-5702

Indicators of Compromise

Unexpected crashes of firefox.exe, firefox-bin, or thunderbird processes correlated with network activity to untrusted hosts.
Crash reports referencing networking stack components in stack traces submitted to local crash handlers.
Browser or mail client versions reported by endpoint inventory as Firefox < 125, Firefox ESR < 115.12, or Thunderbird < 115.12.

Detection Strategies

Inventory all endpoints to identify Firefox and Thunderbird installations below the patched versions.
Monitor for repeated crashes of Mozilla applications across the fleet, which may indicate exploitation attempts or unstable network conditions.
Correlate crash events with outbound network connections to identify potentially malicious servers.

Monitoring Recommendations

Forward browser and mail client crash telemetry to a centralized logging platform for analysis.
Alert on Mozilla application processes spawning child processes such as shells, cmd.exe, or powershell.exe.
Track software inventory changes and flag systems that remain on unpatched versions after the patch window.

How to Mitigate CVE-2024-5702

Immediate Actions Required

Update Mozilla Firefox to version 125 or later on all endpoints.
Update Mozilla Firefox ESR to version 115.12 or later for managed deployments.
Update Mozilla Thunderbird to version 115.12 or later on all systems that process email.
Apply distribution-level updates such as those announced in the Debian LTS Security Announcement.

Patch Information

Mozilla released fixes in Firefox 125, Firefox ESR 115.12, and Thunderbird 115.12. The patches are documented in Mozilla Security Advisory MFSA-2024-18, Mozilla Security Advisory MFSA-2024-26, and Mozilla Security Advisory MFSA-2024-28. Technical details are tracked in Mozilla Bug Report #1193389.

Workarounds

No vendor-supplied workaround exists; patching is the only supported remediation path.
Restrict outbound connections from clients to trusted destinations using network egress controls until patches are deployed.
Enforce automatic updates for Firefox and Thunderbird through enterprise policy to reduce exposure windows.

bash

# Verify installed version on Linux endpoints
firefox --version
thunderbird --version

# Debian/Ubuntu update
sudo apt update && sudo apt install --only-upgrade firefox-esr thunderbird