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);
- CVSS 4.0
- 7.1
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 - CVSS 3.1
- 8.8
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS
- 0.5% chance of exploitation in the next 30 days; higher than 39% of CVEs (scores of 2026-10-25)
- CWE
- CWE-191
- Published
- Modified
- Record from
- the NVD, synced
Affected
- quickjs_project:quickjs