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.
References
| Link | Resource |
|---|---|
| https://bellard.org/quickjs/Changelog | Release Notes |
| https://issuetracker.google.com/434193023 | Exploit Issue Tracking |
Configurations
History
29 Oct 2025, 18:58
| Type | Values Removed | Values Added |
|---|---|---|
| CPE | cpe:2.3:a:quickjs_project:quickjs:*:*:*:*:*:*:*:* | |
| First Time |
Quickjs Project quickjs
Quickjs Project |
|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 8.8 |
| References | () https://bellard.org/quickjs/Changelog - Release Notes | |
| References | () https://issuetracker.google.com/434193023 - Exploit, Issue Tracking |
16 Oct 2025, 16:15
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2025-10-16 16:15
Updated : 2025-10-29 18:58
NVD link : CVE-2025-62494
Mitre link : CVE-2025-62494
CVE.ORG link : CVE-2025-62494
JSON object : View
Products Affected
quickjs_project
- quickjs
CWE
CWE-704
Incorrect Type Conversion or Cast