CVE-2026-25586
SandboxJS has a Sandbox Escape via Prototype Whitelist Bypass and Host Prototype Pollution
- State
- Published
- Severity
- 10.0 Critical
- Published
- Feb 6, 2026
- Updated
- Feb 6, 2026
- Reserved
- Feb 3, 2026
Description
SandboxJS is a JavaScript sandboxing library. Prior to 0.8.29, a sandbox escape is possible by shadowing hasOwnProperty on a sandbox object, which disables prototype whitelist enforcement in the property-access path. This permits direct access to __proto__ and other blocked prototype properties, enabling host Object.prototype pollution and persistent cross-sandbox impact. This vulnerability is fixed in 0.8.29.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 10.0 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H | GitHub_M |
Weaknesses
- CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
Affected Products
| Product | Versions |
|---|---|
SandboxJSnyariv |
|
References
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