# GHSA-6jg8-7333-554w: Sandbox Breakout in realms-shim

> An attacker can escape the sandbox and execute arbitrary code by exploiting a flaw in the Reflect.construct implementation within the realms-shim library.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 Oct 2019

## What is GHSA-6jg8-7333-554w?

GHSA-6jg8-7333-554w is a code injection vulnerability in realms-shim, published on 4 Oct 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Versions of `realms-shim` prior to 1.2.0 are vulnerable to a Sandbox Breakout. `Reflect.construct` can be used on the sandboxed Function constructor to reach the prototypes of the primal Realm, which may allow an attacker to escape the sandbox and execute arbitrary code.

## Recommendation

Upgrade to version 1.2.0 or later.

## Which versions are affected by GHSA-6jg8-7333-554w?

4 open source packages ship an affected version, including realms-shim and ses.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `realms-shim` | npm | All versions | 1.2.0 |
| `realms-shim` | npm | All versions | 1.2.0 |
| `ses` | npm | All versions | 0.6.3 |
| `ses` | npm | All versions | 0.6.3 |

## How do I fix GHSA-6jg8-7333-554w?

Upgrade realms-shim to 1.2.0 or later.

## Is GHSA-6jg8-7333-554w being exploited?

There is no known exploitation of GHSA-6jg8-7333-554w in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-6jg8-7333-554w and fix it if it is affected.

What it is: GHSA-6jg8-7333-554w is a code injection vulnerability in realms-shim, published on 4 Oct 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of GHSA-6jg8-7333-554w in the wild and no public exploit code.

Affected packages and fixed versions:
- realms-shim (npm): affected all versions; fixed in 1.2.0
- realms-shim (npm): affected all versions; fixed in 1.2.0
- ses (npm): affected all versions; fixed in 0.6.3
- ses (npm): affected all versions; fixed in 0.6.3

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/GHSA-6jg8-7333-554w/ (Markdown: https://insights.sbomify.com/GHSA-6jg8-7333-554w/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-6jg8-7333-554w

---
From sbomify Insights: https://insights.sbomify.com/GHSA-6jg8-7333-554w/
Summaries are generated and may contain mistakes; the official description above is the record.