{ "dataType": "CVE_RECORD", "dataVersion": "5.1", "cveMetadata": { "cveId": "CVE-2025-62494", "assignerOrgId": "14ed7db2-1595-443d-9d34-6215bf890778", "state": "PUBLISHED", "assignerShortName": "Google", "dateReserved": "2025-10-15T08:47:41.878Z", "datePublished": "2025-10-16T15:51:50.977Z", "dateUpdated": "2025-10-16T17:46:39.174Z" }, "containers": { "cna": { "affected": [ { "collectionURL": "https://bellard.org/quickjs/", "defaultStatus": "unaffected", "packageName": "JS_ConcatStringInPlace", "product": "QuickJS", "vendor": "QuickJS", "versions": [ { "lessThan": "2025-09-13", "status": "affected", "version": "2025-04-26", "versionType": "date" } ] } ], "credits": [ { "lang": "en", "type": "finder", "value": "Google Big Sleep" } ], "datePublic": "2025-07-24T22:00:00.000Z", "descriptions": [ { "lang": "en", "supportingMedia": [ { "base64": false, "type": "text/html", "value": "

A type confusion vulnerability exists in the handling of the string addition (+) operation within the QuickJS engine.

  1. The code first checks if the left-hand operand is a string.

  2. 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).

  3. 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).

  4. 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.


" } ], "value": "A type confusion vulnerability exists in the handling of the string addition (+) operation within the QuickJS engine.\n\n * The code first checks if the left-hand operand is a string.\n\n\n * 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).\n\n\n * 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).\n\n\n * The code then proceeds to call JS_ConcatStringInPlace, which still treats the modified left-hand value as a string.\n\n\nThis 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." } ], "impacts": [ { "capecId": "CAPEC-175", "descriptions": [ { "lang": "en", "value": "CAPEC-175 Code Inclusion" } ] } ], "metrics": [ { "cvssV4_0": { "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "attackVector": "ADJACENT", "baseScore": 7.1, "baseSeverity": "HIGH", "privilegesRequired": "LOW", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "LOW", "subConfidentialityImpact": "HIGH", "subIntegrityImpact": "HIGH", "userInteraction": "PASSIVE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:A/AC:H/AT:P/PR:L/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L", "version": "4.0", "vulnAvailabilityImpact": "LOW", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnerabilityResponseEffort": "NOT_DEFINED" }, "format": "CVSS", "scenarios": [ { "lang": "en", "value": "GENERAL" } ] } ], "problemTypes": [ { "descriptions": [ { "cweId": "CWE-704", "description": "CWE-704 Incorrect Type Conversion or Cast", "lang": "en", "type": "CWE" } ] } ], "providerMetadata": { "orgId": "14ed7db2-1595-443d-9d34-6215bf890778", "shortName": "Google", "dateUpdated": "2025-10-16T15:51:50.977Z" }, "references": [ { "url": "https://bellard.org/quickjs/Changelog" }, { "url": "https://issuetracker.google.com/434193023" } ], "source": { "discovery": "UNKNOWN" }, "title": "Type confusion in string addition in QuickJS", "x_generator": { "engine": "Vulnogram 0.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2025-10-16T17:46:18.542287Z", "id": "CVE-2025-62494", "options": [ { "Exploitation": "poc" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2025-10-16T17:46:39.174Z" } } ] } }