CVE-2023-34867

What it actually does

An assertion failure in ecma_property_hashmap_create causes the Jerryscript engine to abort when processing certain malformed JavaScript property operations, resulting in an immediate process crash and denial of service.

Why it matters to the business

Services or devices embedding the affected Jerryscript version can be remotely terminated, leading to unplanned downtime and loss of availability for any application relying on the engine.

How an attack unfolds

An attacker supplies specially crafted JavaScript input that reaches the property hashmap creation routine, triggering the assertion failure and crashing the interpreter; public exploit code exists that demonstrates this crash path.

How to fix it

Upgrade to a patched Jerryscript release once available; in the interim, apply input sanitization or sandbox restrictions around untrusted script execution, and monitor upstream commits for the fix in ecma-property-hashmap.c.

How to confirm the fix worked

Confirm the Jerryscript version is newer than commit 05dbbd1, run regression tests that previously triggered the assertion, and verify the engine no longer aborts on the known crashing inputs.

Typical attack path

1. Identify a network-accessible or locally reachable Jerryscript instance
2. Craft or reuse a JavaScript payload that exercises the ecma_property_hashmap_create assertion
3. Deliver the payload via script execution, file load, or network request
4. Observe immediate process termination and service outage

How to detect it

Search process and application logs for sudden Jerryscript terminations, assertion failure messages referencing ecma_property_hashmap_create, or segfault/abort signals immediately following script execution events.

What your security team should do

• Prioritize patching Jerryscript in all embedded or server-side deployments due to available public exploit
• Disable execution of untrusted scripts until mitigation is in place
• Add runtime monitoring for abrupt Jerryscript process exits
• Track upstream repository for the corrected hashmap implementation