CVE-2026-43898
SandboxJS: Sandbox escape via Function.caller leakage of internal call op
- State
- Published
- Severity
- 10.0 Critical
- Published
- May 28, 2026
- Updated
- May 28, 2026
- Reserved
- May 4, 2026
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.
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-94 Improper Control of Generation of Code ('Code Injection')
Affected Products
| Product | Versions |
|---|---|
SandboxJSnyariv |
|
References
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