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CVE-2025-62494— Type confusion in string addition in QuickJS

EPSS 0.01% · P3
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I. Basic Information for CVE-2025-62494

Vulnerability Information

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Vulnerability Title
Type confusion in string addition in QuickJS
Source: NVD (National Vulnerability Database)
Vulnerability Description
A type confusion vulnerability exists in the handling of the string addition (+) operation within the QuickJS engine. * The code first checks if the left-hand operand is a string. * It then attempts to convert the right-hand operand to a primitive value using JS_ToPrimitiveFree. This conversion can trigger a callback (e.g., toString or valueOf). * During this callback, an attacker can modify the type of the left-hand operand in memory, changing it from a string to a different type (e.g., an object or an array). * The code then proceeds to call JS_ConcatStringInPlace, which still treats the modified left-hand value as a string. This mismatch between the assumed type (string) and the actual type allows an attacker to control the data structure being processed by the concatenation logic, resulting in a type confusion condition. This can lead to out-of-bounds memory access, potentially resulting in memory corruption and arbitrary code execution in the context of the QuickJS runtime.
Source: NVD (National Vulnerability Database)
CVSS Information
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Type
不正确的类型转换
Source: NVD (National Vulnerability Database)
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,该漏洞源于处理字符串加法操作时存在类型混淆,可能导致越界内存访问和内存损坏,进而执行任意代码。
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

VendorProductAffected VersionsCPESubscribe
QuickJSQuickJS 2025-04-26 ~ 2025-09-13 -

II. Public POCs for CVE-2025-62494

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III. Intelligence Information for CVE-2025-62494

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

CVE-2025-62492Heap out-of-bounds read in js_typed_array_indexOf in QuickJS
CVE-2025-62493Heap out-of-bounds read in js_bigint_to_string1 in QuickJS
CVE-2025-62495Type confusion in string addition in QuickJS
CVE-2025-62491Use-after-free in js_std_promise_rejection_check in QuickJS
CVE-2025-62490Use-after-free in js_print_object in QuickJS
CVE-2025-62496Integer overflow in js_bigint_from_string in QuickJS

IV. Related Vulnerabilities

V. Comments for CVE-2025-62494

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