What’s Vulnerable › Vulnerabilities

CVE-2026-25587: SandboxJS has a Sandbox Escape

• Severity: critical (CVSS 10.0 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-02-06 · updated 2026-06-17
• Weakness: CWE-94

Description

SandboxJS is a JavaScript sandboxing library. Prior to 0.8.29, as Map is in SAFE_PROTOYPES, it's prototype can be obtained via Map.prototype. By overwriting Map.prototype.has the sandbox can be escaped. This vulnerability is fixed in 0.8.29.

Affected products

• nyariv SandboxJS: before 0.8.29 — fixed in 0.8.29

How to fix

Upgrade to a fixed version: nyariv SandboxJS 0.8.29. Check the vendor advisory for mitigations.

References

• https://github.com/nyariv/SandboxJS/commit/67cb186c41c78c51464f70405504e8ef0a6e43c3
• https://github.com/nyariv/SandboxJS/security/advisories/GHSA-66h4-qj4x-38xp
• https://github.com/nyariv/SandboxJS/security/advisories/GHSA-66h4-qj4x-38xp

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