Sandboxjs
CVE-2026-25587
CRITICAL
GHSA-66h4-qj4x-38xp
Severity by source
AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Primary rating from GitHub Advisory · only source for this CVE.
CVSS VectorGitHub Advisory
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Lifecycle Timeline
4DescriptionGitHub Advisory
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.
AnalysisAI
SandboxJS has a fourth CVSS 10.0 sandbox escape through Map's safe prototype being used as a gateway to inject arbitrary code.
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | SandboxJS versions prior to 0.8.29 with Map included in SAFE_PROTOTYPES. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | CVSS 10.0 with PoC and patch. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker leverages Map's trusted status to inject code that escapes the sandbox. |
| Remediation | Update to 0.8.29+. Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Identify all systems and applications using SandboxJS and assess their exposure to untrusted code sources. …
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External POC / Exploit Code
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