CVE-2026-26954

Received Received - Intake

Sandbox Escape via Function Array in SandboxJS

Publication date: 2026-03-13

Last updated on: 2026-03-17

Assigner: GitHub, Inc.

Description

SandboxJS is a JavaScript sandboxing library. Prior to 0.8.34, it is possible to obtain arrays containing Function, which allows escaping the sandbox. Given an array containing Function, and Object.fromEntries, it is possible to construct {[p]: Function} where p is any constructible property. This vulnerability is fixed in 0.8.34.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-03-13

Last Modified

2026-03-17

Generated

2026-07-06

AI Q&A

2026-03-13

EPSS Evaluated

2026-07-05

NVD

CVE-2026-26954

EUVD

EUVD-2026-12043

Affected Vendors & Products

Vendor	Product	Version / Range
nyariv	sandboxjs	to 0.8.34 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-94	The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

Attack-Flow Graph

Executive Summary

This vulnerability exists in SandboxJS, a JavaScript sandboxing library, in versions prior to 0.8.34. It allows an attacker to obtain arrays containing the Function object, which can be used to escape the sandbox environment. By combining such an array with Object.fromEntries, an attacker can construct an object with properties that reference the Function constructor, enabling execution of arbitrary code outside the sandbox.

Impact Analysis

This vulnerability can have severe impacts because it allows an attacker to escape the sandbox and execute arbitrary code. This can lead to complete compromise of the system running SandboxJS, including unauthorized access, data theft, data modification, and denial of service.

Compliance Impact

I don't know

Detection Guidance

I don't know

Mitigation Strategies

To mitigate this vulnerability, you should upgrade SandboxJS to version 0.8.34 or later, where the issue is fixed.

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