NPM · MAY 2026 · EARLY WARNING

SandboxJS npm Package Sandbox Escape Vulnerability

EARLY WARNING · UNCONFIRMED. This page describes a developing threat that 0Day surfaced from early signals and has not yet independently confirmed. Details may change. Always verify against the primary sources before acting.
GHSA-G8F2-4F4F-5JQWSeverity: HIGH

An early warning has been issued regarding a sandbox escape vulnerability in the SandboxJS npm package. This vulnerability, reportedly due to the exposure of `Function.caller` in sandbox-defined functions, allows sandboxed code to recover internal runtime callbacks and execute arbitrary host JavaScript.

What happened

The SandboxJS npm package is under investigation for a sandbox escape vulnerability tracked as GHSA-G8F2-4F4F-5JQW. This vulnerability appears to allow sandboxed code to recover internal runtime callbacks and execute arbitrary host JavaScript, due to the exposure of `Function.caller` in sandbox-defined functions.

To assess your exposure, check if your project dependencies include @nyariv/sandboxjs. If so, it is recommended to upgrade to the latest version that patches this vulnerability. Additionally, review any custom sandboxed code for potential exploitation.

For more detailed information, consult the primary source at [GHSA-g8f2-4f4f-5jqw](https://github.com/advisories/GHSA-g8f2-4f4f-5jqw). The severity of this issue is currently classified as HIGH, and further details are expected as the investigation progresses.

How 0Day mitigates this

MATCHED TO YOUR ACTUAL DEPENDENCY GRAPH0Day matches every incoming threat signal against your GitHub organization’s full dependency graph, including transitive dependencies. If @nyariv/sandboxjs is anywhere in your dependency tree, the engineers who own the affected repositories get a push alert the moment it is flagged — no manual audit to remember to run.

Read how this differs from waiting on a scanner to catch a known advisory, or see the exact, read-only access 0Day needs to do this for an organization.

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