{"id":"CVE-2025-62495","state":"PUBLISHED","title":"Type confusion in string addition in QuickJS","description":"An integer overflow vulnerability exists in the QuickJS regular expression engine (libregexp) due to an inconsistent representation of the bytecode buffer size.\n\n  *  The regular expression bytecode is stored in a DynBuf structure, which correctly uses a $\\text{size}\\_\\text{t}$ (an unsigned type, typically 64-bit) for its size member.\n\n\n  *  However, several functions, such as re_emit_op_u32 and other internal parsing routines, incorrectly cast or store this DynBuf $\\text{size}\\_\\text{t}$ value into a signed int (typically 32-bit).\n\n\n  *  When a large or complex regular expression (such as those generated by a recursive pattern in a Proof-of-Concept) causes the bytecode size to exceed $2^{31}$ bytes (the maximum positive value for a signed 32-bit integer), the size value wraps around, resulting in a negative integer when stored in the int variable (Integer Overflow).\n\n\n  *  This negative value is subsequently used in offset calculations. For example, within functions like re_parse_disjunction, the negative size is used to compute an offset (pos) for patching a jump instruction.\n\n\n  *  This negative offset is then incorrectly added to the buffer pointer (s->byte\\_code.buf + pos), leading to an out-of-bounds write on the first line of the snippet below:\n\nput_u32(s->byte_code.buf + pos, len);","publishedAt":"2025-10-16T15:51:58.953Z","updatedAt":"2025-10-16T17:42:15.865Z","severity":{"score":7.1,"label":"High","version":"4.0","vector":"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","source":"Google"},"assigner":"Google","products":["QuickJS QuickJS"],"affected":[{"vendor":"QuickJS","product":"QuickJS","packageName":"libregexp","defaultStatus":"unaffected","versions":[{"version":"2025-04-26","status":"affected","lessThan":"2025-09-13","versionType":"date"}],"collectionURL":"https://bellard.org/quickjs/"}],"references":["https://bellard.org/quickjs/Changelog","https://issuetracker.google.com/434196926"],"weaknesses":["CWE-191"],"ingestedAt":"2026-10-29T20:09:48.677Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/62xxx/CVE-2025-62495.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.1","cveMetadata":{"cveId":"CVE-2025-62495","state":"PUBLISHED","datePublished":"2025-10-16T15:51:58.953Z","dateUpdated":"2025-10-16T17:42:15.865Z","assignerShortName":"Google","assignerOrgId":"14ed7db2-1595-443d-9d34-6215bf890778","dateReserved":"2025-10-15T08:47:41.878Z"},"containers":{"cna":{"title":"Type confusion in string addition in QuickJS","descriptions":[{"lang":"en","value":"An integer overflow vulnerability exists in the QuickJS regular expression engine (libregexp) due to an inconsistent representation of the bytecode buffer size.\n\n  *  The regular expression bytecode is stored in a DynBuf structure, which correctly uses a $\\text{size}\\_\\text{t}$ (an unsigned type, typically 64-bit) for its size member.\n\n\n  *  However, several functions, such as re_emit_op_u32 and other internal parsing routines, incorrectly cast or store this DynBuf $\\text{size}\\_\\text{t}$ value into a signed int (typically 32-bit).\n\n\n  *  When a large or complex regular expression (such as those generated by a recursive pattern in a Proof-of-Concept) causes the bytecode size to exceed $2^{31}$ bytes (the maximum positive value for a signed 32-bit integer), the size value wraps around, resulting in a negative integer when stored in the int variable (Integer Overflow).\n\n\n  *  This negative value is subsequently used in offset calculations. For example, within functions like re_parse_disjunction, the negative size is used to compute an offset (pos) for patching a jump instruction.\n\n\n  *  This negative offset is then incorrectly added to the buffer pointer (s->byte\\_code.buf + pos), leading to an out-of-bounds write on the first line of the snippet below:\n\nput_u32(s->byte_code.buf + pos, len);"}],"affected":[{"vendor":"QuickJS","product":"QuickJS","packageName":"libregexp","defaultStatus":"unaffected","versions":[{"version":"2025-04-26","status":"affected","lessThan":"2025-09-13","versionType":"date"}],"collectionURL":"https://bellard.org/quickjs/"}],"references":[{"url":"https://bellard.org/quickjs/Changelog"},{"url":"https://issuetracker.google.com/434196926"}],"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-191","description":"CWE-191 Integer Underflow (Wrap or Wraparound)","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"Google","orgId":"14ed7db2-1595-443d-9d34-6215bf890778","dateUpdated":"2025-10-16T15:51:58.953Z"},"credits":[{"lang":"en","type":"finder","value":"Google Big Sleep"}],"datePublic":"2025-07-24T22:00:00.000Z","impacts":[{"capecId":"CAPEC-175","descriptions":[{"lang":"en","value":"CAPEC-175 Code Inclusion"}]}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 0.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2025-10-16T17:40:14.439633Z","id":"CVE-2025-62495","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2025-10-16T17:42:15.865Z"}}]}}}