What’s Vulnerable › Vulnerabilities

CVE-2026-43898: SandboxJS: Sandbox escape via Function.caller leakage of internal call op

• Severity: critical (CVSS 10.0 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-05-28 · updated 2026-10-14
• Weakness: CWE-94

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.

Affected products

• nyariv SandboxJS: before 0.9.6 — fixed in 0.9.6

How to fix

Upgrade to a fixed version: nyariv SandboxJS 0.9.6. Check the vendor advisory for mitigations.

References

• https://github.com/nyariv/SandboxJS/commit/826865251232611ec94078bab5a18ec875dad4a5
• https://github.com/nyariv/SandboxJS/security/advisories/GHSA-g8f2-4f4f-5jqw
• https://github.com/nyariv/SandboxJS/security/advisories/GHSA-g8f2-4f4f-5jqw

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