CVE-2026-43898
published 2026-05-28CVE-2026-43898: SandboxJS is a JavaScript sandboxing library. Prior to 0.9.6, sandbox-defined functions expose Function.caller, allowing sandboxed code to recover the internal…
PriorityP263critical10CVSS 3.1
AVNACLPRNUINSCCHIHAH
EPSS
0.47%
37.3th percentile
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.
Affected
2 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| nyariv | sandboxjs | < 0.9.6 | 0.9.6 |
| nyariv | sandboxjs | >= 0 < 0.9.6 | 0.9.6 |
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VulDB
nyariv SandboxJS up to 0.9.5 code injection (EUVD-2026-32968)
vuldb·2026-05-28·CVSS 10.0
CVE-2026-43898 [CRITICAL] nyariv SandboxJS up to 0.9.5 code injection (EUVD-2026-32968)
A vulnerability was found in nyariv SandboxJS up to 0.9.5. It has been rated as critical. The impacted element is an unknown function. This manipulation causes code injection.
This vulnerability is registered as CVE-2026-43898. Remote exploitation of the attack is possible. No exploit is available.
Upgrading the affected component is advised.
GHSA
SandboxJS has a sandbox escape via Function.caller leakage of internal call op
ghsa·2026-05-11
CVE-2026-43898 [CRITICAL] CWE-94 SandboxJS has a sandbox escape via Function.caller leakage of internal call op
SandboxJS has a sandbox escape via Function.caller leakage of internal call op
### Summary
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.
### Details
In [executorUtils.ts](https://github.com/nyariv/SandboxJS/blob/1e6785658c94f5f2fb8e4a02cfcf1e7821b8be7f/src/executor/executorUtils.ts#L239-L282) `createFunction()` constructs normal host JS functions, and because these are ordinary host functions, sandbox code can observe:
```js
function f(){ return f.caller }
```
That leaks the host-side callback that invo
No detection rules found.
No public exploits indexed.
2026-05-28
Published