CVE-2025-62491
Severity CVSS v4.0:
HIGH
Type:
CWE-416
Use After Free
Publication date:
16/10/2025
Last modified:
30/10/2025
Description
A Use-After-Free (UAF) vulnerability exists in the QuickJS engine&#39;s standard library when iterating over the global list of unhandled rejected promises (ts->rejected_promise_list).<br />
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* The function js_std_promise_rejection_check attempts to iterate over the rejected_promise_list to report unhandled rejections using a standard list loop.<br />
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* The reason for a promise rejection is processed inside the loop, including calling js_std_dump_error1(ctx, rp->reason).<br />
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* If the promise rejection reason is an Error object that defines a custom property getter (e.g., via Object.defineProperty), this getter is executed during the error dumping process.<br />
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* The malicious custom getter can execute JavaScript code that calls catch() on the same rejected promise being processed.<br />
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* Calling catch() internally triggers js_std_promise_rejection_tracker, which then removes and frees the current promise entry (JSRejectedPromiseEntry) from the rejected_promise_list.<br />
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* Since the list iteration continues using the now-freed memory pointer (el), the subsequent loop access results in a Use-After-Free condition.
Impact
Base Score 4.0
8.80
Severity 4.0
HIGH
Base Score 3.x
8.80
Severity 3.x
HIGH
Vulnerable products and versions
| CPE | From | Up to |
|---|---|---|
| cpe:2.3:a:quickjs_project:quickjs:*:*:*:*:*:*:*:* | 2025-09-13 (excluding) |
To consult the complete list of CPE names with products and versions, see this page