CVE-2026-43898

CRITICAL

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

Title source: cna
STIX 2.1

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.

References (2)

Core 2

Scores

CVSS v3 10.0
EPSS 0.0047
EPSS Percentile 36.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact total

Details

CWE
CWE-94
Status published
Products (3)
nyariv/sandboxjs < 0.9.6
nyariv/sandboxjs 0 - 0.9.6npm
nyariv/SandboxJS < 0.9.6
Published May 28, 2026
Tracked Since May 28, 2026