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CVE-2025-62491— Use-after-free in js_std_promise_rejection_check in QuickJS

Quick assessment

Affected
QuickJS QuickJS
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

QuickJS是QuickJS开源的一个小型且可嵌入的 Javascript 引擎。 QuickJS存在安全漏洞，该漏洞源于处理未处理拒绝承诺列表时存在释放后重用问题，可能导致内存损坏。

AI Predicted 9.8 Difficulty: Moderate EPSS 0.41% · P33

Possible ATT&CK Techniques 1 AI

T1203 · Exploitation for Client Execution
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I. Basic Information for CVE-2025-62491

Vulnerability Information
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Vulnerability Title
Use-after-free in js_std_promise_rejection_check in QuickJS
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L
Source: CVE Program / CVE List V5
Vulnerability Type
释放后使用
Source: CVE Program / CVE List V5
Vulnerability Title
QuickJS 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
QuickJS是QuickJS开源的一个小型且可嵌入的 Javascript 引擎。 QuickJS存在安全漏洞，该漏洞源于处理未处理拒绝承诺列表时存在释放后重用问题，可能导致内存损坏。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
QuickJS QuickJS 2025-04-26 ~ 2025-09-13 -

II. Public POCs for CVE-2025-62491

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III. Intelligence Information for CVE-2025-62491

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Other References for CVE-2025-62491 (1)

Same Patch Batch · QuickJS · 2025-10-16 · 7 CVEs total

CVE-2025-62492 Heap out-of-bounds read in js_typed_array_indexOf in QuickJS
CVE-2025-62493 Heap out-of-bounds read in js_bigint_to_string1 in QuickJS
CVE-2025-62494 Type confusion in string addition in QuickJS
CVE-2025-62495 Type confusion in string addition in QuickJS
CVE-2025-62490 Use-after-free in js_print_object in QuickJS
CVE-2025-62496 Integer overflow in js_bigint_from_string in QuickJS

IV. Related Vulnerabilities

Same product: QuickJS
Same vendor: QuickJS
Same weakness: CWE-416

V. Comments for CVE-2025-62491

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