{"id":"CVE-2025-62495","details":"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-\u003ebyte\\_code.buf + pos), leading to an out-of-bounds write on the first line of the snippet below:\n\nput_u32(s-\u003ebyte_code.buf + pos, len);","modified":"2026-04-10T05:33:06.759934Z","published":"2025-10-16T16:15:40.110Z","references":[{"type":"ADVISORY","url":"https://bellard.org/quickjs/Changelog"},{"type":"REPORT","url":"https://issuetracker.google.com/434196926"}],"affected":[{"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-62495.json","unresolved_ranges":[{"events":[{"introduced":"0"},{"fixed":"2025-09-13"}]}]}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}