# CVE-2019-10769: safer-eval sandbox breakout and arbitrary code execution

Source: https://junglewise.ai/threats/cve-2019-10769-safer-eval-sandbox-breakout-and-arbitrary-code-execution  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2019-12-11. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2019-10769 · Severity: low · CVSS 3.1 · Published 2019-12-11

safer-eval is a Node.js library designed to safely evaluate code expressions in a sandboxed environment. A critical vulnerability allows attackers to escape the sandbox and execute arbitrary code on the system. Any application using safer-eval to process untrusted user input is at risk of complete system compromise.

Technologies: [safer-eval (npm)](https://junglewise.ai/threats/technologies/safer-eval). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2019-10769 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2019-10769 being exploited in the wild.

**How severe is CVE-2019-10769?** Low severity, with a CVSS score of 3.1, published 11 December 2019.

**Which products and versions are affected?** safer-eval (npm) 0.0.0 and all versions up to 1.3.6.

**Is there a fix for CVE-2019-10769?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2019-10769 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2019-10769?** Check whether you run safer-eval (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

safer-eval contains an insufficient input validation and improper sandbox isolation vulnerability (CWE-20, CWE-94) that allows attackers to break out of the intended sandbox environment. The package fails to properly restrict access to the main JavaScript context, allowing an attacker to bypass intended security boundaries. No authentication or special preconditions are required—any user input passed to safer-eval can be exploited. A successful exploit grants an attacker arbitrary code execution with the privileges of the Node.js process. No patch has been released; the maintainers recommend switching to alternative packages such as vm2.

## Affected products

- npm safer-eval 0.0.0 and all versions up to 1.3.6

## Identifiers

- CVE-2019-10769
- GHSA-v63x-xc9j-hhvq

## Timeline

- 2019-12-06: disclosed: Original disclosure
- 2019-12-11: advisory: GHSA-v63x-xc9j-hhvq published

## References

- [https://github.com/commenthol/safer-eval/security/advisories/GHSA-v63x-xc9j-hhvq](https://github.com/commenthol/safer-eval/security/advisories/GHSA-v63x-xc9j-hhvq)

## Related threats

- [safer-eval sandbox breakout arbitrary code execution](https://junglewise.ai/threats/safer-eval-sandbox-breakout-arbitrary-code-execution-6fed75c1)
- [safer-eval sandbox breakout via Object.constructor](https://junglewise.ai/threats/safer-eval-sandbox-breakout-via-object-constructor-d8e87f1c)
- [safer-eval sandbox escape and arbitrary code execution](https://junglewise.ai/threats/cve-2019-10759-safer-eval-sandbox-escape-and-arbitrary-code-execution)
- [safer-eval sandbox escape via constructor property](https://junglewise.ai/threats/cve-2019-10760-safer-eval-sandbox-escape-via-constructor-property)