CVE-2025-65570
Published: 29 December 2025
Description
A type confusion in jsish 2.0 allows incorrect control flow during execution of the OP_NEXT opcode. When an “instanceof” expression uses an array element access as the left-hand operand inside a for-in loop, the instructions implementation leaves an additional array…
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reference on the stack rather than consuming it during OP_INSTANCEOF. As a result, OP_NEXT interprets the array as an iterator object and reads the iterCmd function pointer from an invalid structure, potentially causing a crash or enabling code execution depending on heap layout.
Mitigating Controls (NIST 800-53 r5)AI
SI-2 mandates timely identification, testing, and installation of patches or upgrades for jsish to remediate the type confusion vulnerability in OP_NEXT opcode execution.
SI-16 implements memory safeguards like ASLR and DEP to mitigate arbitrary code execution from type confusion-induced invalid function pointer reads dependent on heap layout.
RA-5 requires vulnerability scanning to detect CVE-2025-65570 in jsish deployments and initiate risk-based remediation to prevent remote exploitation.
Security SummaryAI
CVE-2025-65570 is a type confusion vulnerability in jsish 2.0, published on 2025-12-29. The issue arises during execution of the OP_NEXT opcode when an "instanceof" expression uses an array element access as the left-hand operand inside a for-in loop. The implementation fails to consume the array reference during OP_INSTANCEOF, leaving it on the stack. Consequently, OP_NEXT misinterprets the array as an iterator object and reads the iterCmd function pointer from an invalid structure, which can lead to a crash or code execution depending on heap layout. It carries a CVSS score of 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) and is associated with CWE-843.
Attackers can exploit this vulnerability remotely over the network with low attack complexity, requiring no privileges, authentication, or user interaction. Successful exploitation allows high-impact confidentiality, integrity, and availability violations, ranging from application crashes to arbitrary code execution contingent on memory layout.
Details on the vulnerability, including a writeup, are provided at https://blog.mcsky.ro/writeups/2025/11/15/inline8-writeup.html. No mitigation or patch information is specified in the available data.
Details
- CWE(s)
Affected Products
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The vulnerability allows remote, unauthenticated arbitrary code execution or denial of service in a network-accessible JavaScript interpreter (jsish), directly mapping to exploitation of a public-facing application.