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);
References
| Link | Resource |
|---|---|
| https://bellard.org/quickjs/Changelog | Release Notes |
| https://issuetracker.google.com/434196926 | Exploit Issue Tracking |
Configurations
History
29 Oct 2025, 18:56
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://bellard.org/quickjs/Changelog - Release Notes | |
| References | () https://issuetracker.google.com/434196926 - Exploit, Issue Tracking | |
| CPE | cpe:2.3:a:quickjs_project:quickjs:*:*:*:*:*:*:*:* | |
| First Time |
Quickjs Project quickjs
Quickjs Project |
|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 8.8 |
16 Oct 2025, 16:15
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2025-10-16 16:15
Updated : 2025-10-29 18:56
NVD link : CVE-2025-62495
Mitre link : CVE-2025-62495
CVE.ORG link : CVE-2025-62495
JSON object : View
Products Affected
quickjs_project
- quickjs
CWE
CWE-191
Integer Underflow (Wrap or Wraparound)