CVE-2026-43898

SandboxJS: Sandbox escape via Function.caller leakage of internal call op

Published May 28, 2026 CVSS 3.1 · 10 Critical EPSS < 1% KEV · Not listed
Description
SandboxJS is a JavaScript sandboxing library. Prior to 0.9.6, sandbox-defined functions expose Function.caller, allowing sandboxed code to recover the internal LispType.Call runtime callback. That callback can then be invoked with attacker-controlled fake context and obj values to extract blocked host statics, recover the real host Function constructor, and execute arbitrary host JavaScript. This vulnerability is fixed in 0.9.6.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-g8f2-4f4f-5jqw SandboxJS has a sandbox escape via Function.caller leakage of internal call op
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Nyariv
Nyariv sandboxjs
CPEs cpe:2.3:a:nyariv:sandboxjs:*:*:*:*:*:node.js:*:*
Vendors & Products Nyariv
Nyariv sandboxjs
Type Values Removed Values Added
Description SandboxJS is a JavaScript sandboxing library. Prior to 0.9.6, sandbox-defined functions expose Function.caller, allowing sandboxed code to recover the internal LispType.Call runtime callback. That callback can then be invoked with attacker-controlled fake context and obj values to extract blocked host statics, recover the real host Function constructor, and execute arbitrary host JavaScript. This vulnerability is fixed in 0.9.6.
Title SandboxJS: Sandbox escape via Function.caller leakage of internal call op
Weaknesses CWE-94
References
Metrics cvssV3_1

{'score': 10, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
May 28, 2026, 7:32 PM
Reserved
May 4, 2026, 4:11 PM
Status
Modified
Published
May 28, 2026, 6:16 PM
Modified
Oct 14, 2026, 8:10 PM