SecuriTricks - 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->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);

Product(s) Impacted

Vendor	Product	Versions
Quickjs	Libregexp	*

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-191

Integer Underflow (Wrap or Wraparound)

The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.

*CPE(s)

Affected systems and software identified for this CVE.

Type	Vendor	Product	Version	Update	Edition	Language	Software Edition	Target Software	Target Hardware	Other Information
a	quickjs	libregexp	/	/	/	/	/	/	/	/

References

https://bellard.org/quickjs/Changelog

https://issuetracker.google.com/434196926

CVSS Score

7.1 / 10

CVSS Data - 4.0

Attack Vector: ADJACENT
Attack Complexity: HIGH
Attack Requirements: PRESENT
Privileges Required: LOW
User Interaction: PASSIVE
Scope:
Confidentiality Impact: HIGH
Integrity Impact: HIGH
Availability Impact: LOW
Exploit Maturity: NOT_DEFINED

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

View Vector String

Timeline

Published: Oct. 16, 2025, 4:15 p.m.
Last Modified: Oct. 16, 2025, 4:15 p.m.

Status : Received

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

cve-coordination@google.com

CVE-2025-62495