Type Confusion Vulnerability in QuickJS Engine Affecting Multiple Versions
CVE-2025-62494

7.1HIGH

Key Information:

Vendor

Quickjs

Status
Quickjs
Vendor
CVE Published:
16 October 2025

What is CVE-2025-62494?

A type confusion vulnerability exists in the QuickJS engine's handling of string addition operations. The issue arises when the left-hand operand is verified as a string while the right-hand operand undergoes conversion that can allow an attacker to modify the type of the left operand during execution. This change creates a mismatch that leads to improper handling within the concatenation logic. Such discrepancies may result in out-of-bounds memory access, ultimately exposing systems to memory corruption and potential arbitrary code execution within the QuickJS runtime.

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Affected Version(s)

QuickJS 2025-04-26 < 2025-09-13

References

https://bellard.org/quickjs/Changelog
https://issuetracker.google.com/434193023

CVSS V4

Score:
7.1
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
Low
Attack Vector:
Adjacent Network
Attack Complexity:
High
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Google Big Sleep
JSON
.