Vulnerability Details CVE-2025-62495
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->byte\_code.buf + pos), leading to an out-of-bounds write on the first line of the snippet below:
put_u32(s->byte_code.buf + pos, len);
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 11.7%
CVSS Severity
CVSS v3 Score 8.8
Products affected by CVE-2025-62495
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cpe:2.3:a:quickjs_project:quickjs:-
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cpe:2.3:a:quickjs_project:quickjs:2019-07-09
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cpe:2.3:a:quickjs_project:quickjs:2019-07-21
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cpe:2.3:a:quickjs_project:quickjs:2019-07-28
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cpe:2.3:a:quickjs_project:quickjs:2019-08-10
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cpe:2.3:a:quickjs_project:quickjs:2019-08-18
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cpe:2.3:a:quickjs_project:quickjs:2019-09-01
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cpe:2.3:a:quickjs_project:quickjs:2019-09-18
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cpe:2.3:a:quickjs_project:quickjs:2019-10-27
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cpe:2.3:a:quickjs_project:quickjs:2019-12-21
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cpe:2.3:a:quickjs_project:quickjs:2020-01-05
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cpe:2.3:a:quickjs_project:quickjs:2020-01-19
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cpe:2.3:a:quickjs_project:quickjs:2020-03-16
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cpe:2.3:a:quickjs_project:quickjs:2020-04-12
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cpe:2.3:a:quickjs_project:quickjs:2020-07-05
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cpe:2.3:a:quickjs_project:quickjs:2020-09-06
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cpe:2.3:a:quickjs_project:quickjs:2020-11-08
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cpe:2.3:a:quickjs_project:quickjs:2021-03-27
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cpe:2.3:a:quickjs_project:quickjs:2022-03-06
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cpe:2.3:a:quickjs_project:quickjs:2023-12-09
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cpe:2.3:a:quickjs_project:quickjs:2024-01-13