CVE-2021-46337

What it actually does

An assertion failure in the JavaScript parser's memory management routine causes an immediate process abort when parsing specially crafted input.

Why it matters to the business

Applications or devices embedding the engine can be forced offline, interrupting any service that relies on JavaScript execution and requiring manual restart.

How an attack unfolds

An attacker supplies a malicious JavaScript file or snippet that reaches the parser_list_get function with a null page pointer, triggering the assertion and crashing the process; public exploit code is available to automate this.

How to fix it

Upgrade to a patched release of JerryScript once available; until then, sandbox or isolate the engine, reject untrusted scripts, or disable JavaScript processing where feasible.

How to confirm the fix worked

Rebuild with assertions enabled and feed known trigger inputs; confirm the process no longer aborts and review commit history for parser memory fixes.

Typical attack path

1. Identify a target process or device that uses the vulnerable JavaScript engine
2. Craft or obtain a minimal JavaScript payload that triggers the parser assertion
3. Deliver the payload via file, network message, or script tag accepted by the target
4. Observe process termination and service outage

How to detect it

Look for unexpected process crashes or segmentation faults in binaries linked against the engine shortly after JavaScript parsing activity; correlate with log entries showing parser entry points.

What your security team should do

• Inventory all products and firmware that embed JerryScript
• Apply updates as soon as fixed versions are published
• Implement input filtering or sandboxing around script execution
• Monitor vendor advisories for backported patches