CVE intelligence and bounded remediation

CVE-2025-62491 — Quickjs Project Quickjs security vulnerability

High CVSS 8.8

A Use-After-Free (UAF) vulnerability exists in the QuickJS engine's standard library when iterating over the global list of unhandled rejected promises (ts->rejected_promise_list). * The function js_std_promise_rejection_check attempts to iterate over the rejected_promise_list to report unhandled rejections using a standard list loop. * The reason for a promise rejection is processed inside the loop, including calling js_std_dump_error1(ctx, rp->reason). * 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. * The malicious custom getter can execute JavaScript code that calls catch() on the same rejected promise being processed. * Calling catch() internally triggers js_std_promise_rejection_tracker, which then removes and frees the current promise entry (JSRejectedPromiseEntry) from the rejected_promise_list. * Since the list iteration continues using the now-freed memory pointer (el), the subsequent loop access results in a Use-After-Free condition.

Severity
High
CVSS
8.8 (4.0)
Published
2025-10-16
CISA KEV
Not currently listed
Ecosystem
javascript/npm
Weaknesses
CWE-416

Affected products

  • quickjs_project / quickjs

Matched remediation archetype

Use-after-free, double free, and expired resource use

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace ownership, references, callbacks, asynchronous tasks, and teardown paths around the affected object or resource.
  • Identify reachable inputs and timing or state transitions that can release the object while references remain.
  • Confirm affected builds, allocators, feature flags, architectures, and process privileges.

Remediate safely

  • Apply the maintained ownership or lifetime fix and rebuild all artifacts containing the affected native code.
  • Use explicit ownership, safe reference management, cancellation and join semantics, and idempotent teardown.
  • Add deterministic lifetime tests plus isolated sanitizer and concurrency coverage for shutdown and error paths.

Authoritative sources

Complete CVE record and remediation plan

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