What’s Vulnerable › Vulnerabilities

CVE-2026-25520: SandboxJS has a Sandbox Escape

• Severity: critical (CVSS 10.0 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-02-06 · updated 2026-06-17
• Weakness: CWE-74

Description

SandboxJS is a JavaScript sandboxing library. Prior to 0.8.29, The return values of functions aren't wrapped. Object.values/Object.entries can be used to get an Array containing the host's Function constructor, by using Array.prototype.at you can obtain the hosts Function constructor, which can be used to execute arbitrary code outside of the sandbox. 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-58jh-xv4v-pcx4
• https://github.com/nyariv/SandboxJS/security/advisories/GHSA-58jh-xv4v-pcx4

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