Host code execution via JSPI Promise species bypass
Published Jun 12, 2026 · Updated Jun 12, 2026
Sandbox escape in vm2 before 3.11.4 allows attackers to execute arbitrary code in the host process through a JSPI-backed Promise. WebAssembly.promising creates a sandbox-visible Promise whose host-realm prototype lets Promise.prototype.finally invoke attacker-controlled species logic with an unwrapped host rejection object. Exploitation requires untrusted asynchronous code and a runtime exposing WebAssembly.promising and WebAssembly.Suspending, such as Node.js 26.
Summary
What happened
Sandbox escape in vm2 before 3.11.4 allows attackers to execute arbitrary code in the host process through a JSPI-backed Promise. WebAssembly.promising creates a sandbox-visible Promise whose host-realm prototype lets Promise.prototype.finally invoke attacker-controlled species logic with an unwrapped host rejection object. Exploitation requires untrusted asynchronous code and a runtime exposing WebAssembly.promising and WebAssembly.Suspending, such as Node.js 26.
The record
- CVE
- CVE-2026-47210
- Published
- Jun 12, 2026
- Updated
- Jun 12, 2026
- Vendor
- Patrik Simek
- Product
- vm2
- Classifications
- CWE-913, T1059.007
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 12, 2026CVE publishedPublication date reported by the CVE source.
- Jun 12, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 3.11.4
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Upstream JSPI Promise species sandbox-escape proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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