# SandboxJS has a sandbox escape via Function.caller leakage of internal call op

Advisory record · `GHSA-g8f2-4f4f-5jqw`

- **Identifiers:** `GHSA-g8f2-4f4f-5jqw` · `CVE-2026-43898`
- **State:** Confirmed
- **Severity:** CVSS 10.0 Critical
- **Critical:** Yes: CVSS 9+
- **Weakness (CWE):** [CWE-94](https://cwe.mitre.org/data/definitions/94.html)
- **Tags:** [Code injection](https://agentprime.io/advisories/tag/code-injection.md)
- **Published:** 11 May 2026
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 11 May 2026, 19:40 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Critical

Critical, because:

- CVSS score 10.0: 9.0 or more.

How we decide what’s critical: <https://agentprime.io/advisories/critical.md>

## Affected packages

- `@nyariv/sandboxjs` (npm): affected `<0.9.6`; fixed in `0.9.6`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 10.0 Critical, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0047, the 41st percentile, on 14 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the GitHub Advisory Database, published 11 May 2026. New records show when each source confirmed them.

## Sources

- [GitHub Advisory Database: GHSA-g8f2-4f4f-5jqw](https://github.com/advisories/GHSA-g8f2-4f4f-5jqw)
- [OSV: GHSA-g8f2-4f4f-5jqw](https://osv.dev/vulnerability/GHSA-g8f2-4f4f-5jqw)
- <https://github.com/nyariv/SandboxJS/security/advisories/GHSA-g8f2-4f4f-5jqw>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-43898>
- <https://github.com/nyariv/SandboxJS/commit/826865251232611ec94078bab5a18ec875dad4a5>
- <https://github.com/nyariv/SandboxJS>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-g8f2-4f4f-5jqw>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-g8f2-4f4f-5jqw/>. Everything for agents: <https://agentprime.io/llms.txt>.