CVE-2024-3852

What it actually does

JIT mis-optimization in GetBoundName returns an incorrect object version, enabling memory corruption (type confusion or use-after-free) that can be leveraged for arbitrary code execution within the browser process.

Why it matters to the business

Successful exploitation can result in full compromise of the user's browser session, allowing theft of credentials, session data, or installation of malware with minimal user interaction beyond visiting a malicious page.

How an attack unfolds

An attacker hosts a specially crafted web page containing JavaScript that forces the JIT compiler to optimize GetBoundName incorrectly; when the victim loads the page, the resulting memory corruption is turned into code execution, potentially installing further payloads.

How to fix it

Upgrade Firefox to version 125 or later, Firefox ESR to 115.10 or later, and Thunderbird to 115.10 or later. Apply updates through the browser's built-in update mechanism or package manager as soon as available.

How to confirm the fix worked

Verify installed browser versions meet or exceed the fixed releases listed above; re-test affected JavaScript constructs in a controlled environment after patching to confirm the optimization issue no longer occurs.

Typical attack path

1. Attacker prepares malicious JavaScript targeting the JIT flaw
2. Victim is lured to the attacker-controlled page via phishing or compromised site
3. Page triggers JIT compilation of the vulnerable function
4. Incorrect object version leads to memory corruption
5. Attacker chains corruption into arbitrary read/write and remote code execution

How to detect it

Review browser process crash logs and telemetry for repeated JIT-related faults; correlate with web proxy logs showing visits to newly registered or suspicious domains around the time of any anomalous browser behavior.

What your security team should do

• Prioritize browser updates across all endpoints within the next 48 hours
• Enable automatic updates for Firefox and Thunderbird where possible
• Block known malicious domains associated with browser exploitation campaigns at the proxy or DNS layer
• Monitor for unusual browser crashes or process anomalies that may indicate attempted exploitation