# CVE-2025-65570: Memory corruption in n/a

> A type confusion in the jsish JavaScript engine allows attackers to cause crashes or execute arbitrary code via crafted instanceof expressions in for-in loops.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Dec 2025
- **Updated:** 31 Dec 2025
- **Also known as:** GHSA-r6xg-3mr4-3226

## What is CVE-2025-65570?

CVE-2025-65570 is a critical memory corruption vulnerability in Jsish Jsish, published on 29 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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 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.

Weakness: CWE-843 (Access of Resource Using Incompatible Type)

## Which versions are affected by CVE-2025-65570?

It affects 1 product.


Products: Jsish Jsish.

## How do I fix CVE-2025-65570?

No fix has been published for CVE-2025-65570 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-65570 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-65570 exists.

## Other vulnerabilities in Jsish Jsish

- [CVE-2024-24186](https://insights.sbomify.com/CVE-2024-24186/): Denial of service in n/a (critical 9.8)
- [CVE-2024-24188](https://insights.sbomify.com/CVE-2024-24188/): Memory corruption in n/a (critical 9.8)
- [CVE-2024-24189](https://insights.sbomify.com/CVE-2024-24189/): Use after free in n/a (critical 9.8)
- [CVE-2020-22873](https://insights.sbomify.com/CVE-2020-22873/): Memory corruption in n/a (critical 9.8)
- [CVE-2020-22874](https://insights.sbomify.com/CVE-2020-22874/): Integer overflow in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-65570 and fix it if it is affected.

What it is: CVE-2025-65570 is a critical memory corruption vulnerability in Jsish Jsish, published on 29 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-65570 exists.

Affected product: Jsish Jsish. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-65570/ (Markdown: https://insights.sbomify.com/CVE-2025-65570/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-65570
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-65570
- OSV: https://osv.dev/vulnerability/CVE-2025-65570

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-65570/
Summaries are generated and may contain mistakes; the official description above is the record.