{"id":"CVE-2025-62495","aliases":["DEBIAN-CVE-2025-62495","EUVD-2025-34779","GHSA-g8rq-rjvv-4hcc","UBUNTU-CVE-2025-62495"],"status":"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-\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);","severity":{"version":"4.0","score":7.1,"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","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00468,"percentile":0.41,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-191"],"published":"2025-10-16T15:51:58Z","modified":"2026-10-23T17:47:38Z","affected":[{"source":"osv","ecosystem":"Debian:13","package":"quickjs","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2025.04.26-1"]},{"source":"osv","ecosystem":"Debian:14","package":"quickjs","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2025.04.26-1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:24.04:LTS","package":"quickjs","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2021.03.27-1","2021.03.27-1ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:25.10","package":"quickjs","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2024.01.13-5","2025.04.26-1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"quickjs","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2025.04.26-1build1"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"quickjs","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2025.04.26-1","2025.04.26-1build1"]}],"products":[{"vendor":"quickjs","product":"quickjs"},{"vendor":"quickjs-ng","product":"quickjs"},{"vendor":"quickjs_project","product":"quickjs"}],"references":[{"url":"https://bellard.org/quickjs/Changelog","tags":["Release Notes","advisory","report"]},{"url":"https://issuetracker.google.com/434196926","tags":["Exploit","Issue Tracking","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-62495"},{"url":"https://github.com/advisories/GHSA-g8rq-rjvv-4hcc"},{"url":"https://security-tracker.debian.org/tracker/CVE-2025-62495","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2025-62495","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2025-62495","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2025-62495","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-\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);","status":"published","published":"2025-10-16T15:51:58.953Z","modified":"2025-10-16T17:42:15.865Z","cvss":[{"version":"4.0","score":7.1,"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","level":"high","assessor":"cna"}],"cwes":["CWE-191"],"updated_at":"2026-11-02T14:32:55.19484Z"}],"euvd":[{"id":"EUVD-2025-34779","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-\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);","status":"published","published":"2025-10-16T15:51:58Z","modified":"2025-10-16T17:42:15Z","cvss":[{"version":"4.0","score":7.1,"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","level":"high"}],"updated_at":"2026-11-02T20:31:31.065489Z"}],"ghsa":[{"id":"GHSA-g8rq-rjvv-4hcc","title":"An integer overflow vulnerability exists in the QuickJS regular expression engine (libregexp) due...","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-\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);","status":"published","published":"2025-10-16T18:30:24Z","modified":"2025-10-29T21:31:41Z","cvss":[{"version":"4.0","score":7.1,"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high"},{"version":"3.1","score":8.8,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-191"],"updated_at":"2026-11-02T15:04:15.305123Z"}],"nvd":[{"id":"CVE-2025-62495","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-\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);","status":"published","published":"2025-10-16T16:15:40.11Z","modified":"2026-10-19T16:10:00.26Z","cvss":[{"version":"4.0","score":7.1,"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high","assessor":"secondary"},{"version":"3.1","score":8.8,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"primary"}],"cwes":["CWE-191"],"updated_at":"2026-11-02T14:11:39.069866Z"}],"osv":[{"id":"CVE-2025-62495","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-\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);","status":"published","published":"2025-10-16T16:15:40.11Z","modified":"2026-04-10T05:33:06.759934Z","cvss":[{"version":"3.1","score":8.8,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T15:44:51.851511Z"},{"id":"DEBIAN-CVE-2025-62495","description":"An integer overflow vulnerability exists in the QuickJS regular expression engine (libregexp) due to an inconsistent representation of the bytecode buffer size.    *  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.     *  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).     *  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).     *  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.     *  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:  put_u32(s-\u003ebyte_code.buf + pos, len);","status":"published","published":"2025-10-16T16:15:40.11Z","modified":"2026-10-23T17:47:38.028546384Z","cvss":[{"version":"3.1","score":8.8,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T15:45:47.697959Z"},{"id":"UBUNTU-CVE-2025-62495","description":"An integer overflow vulnerability exists in the QuickJS regular expression engine (libregexp) due to an inconsistent representation of the bytecode buffer size.   *  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.   *  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).   *  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).   *  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.   *  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: put_u32(s-\u003ebyte_code.buf + pos, len);","status":"published","published":"2025-10-16T16:15:00Z","modified":"2026-10-17T12:58:38.060879736Z","cvss":[{"version":"4.0","score":7.1,"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","level":"high"},{"version":"3.1","score":8.8,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T16:55:50.817402Z"}]}}