Host command execution via mutable Promise species reset
Published May 4, 2026 · Updated May 4, 2026
Code injection in Patrik Simek vm2 before 3.10.5 allows attackers to escape a sandbox and execute commands on the host system. The resetPromiseSpecies function trusts sandbox-mutable [].includes and Object.defineProperty methods, allowing malicious code to preserve a forged Promise species and recover the host Function constructor. Exploitation requires attacker-controlled JavaScript to run inside a vm2 sandbox; successful escape grants the sandboxed code the host process's command-execution privileges.
Summary
What happened
Code injection in Patrik Simek vm2 before 3.10.5 allows attackers to escape a sandbox and execute commands on the host system. The resetPromiseSpecies function trusts sandbox-mutable [].includes and Object.defineProperty methods, allowing malicious code to preserve a forged Promise species and recover the host Function constructor. Exploitation requires attacker-controlled JavaScript to run inside a vm2 sandbox; successful escape grants the sandboxed code the host process's command-execution privileges.
The record
- CVE
- CVE-2026-24120
- Published
- May 4, 2026
- Updated
- May 4, 2026
- Vendor
- Patrik Simek
- Product
- vm2
- Classifications
- CWE-807, CWE-94, CWE-693, T1059.007
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 4, 2026CVE publishedPublication date reported by the CVE source.
- May 4, 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=< 3.10.5
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 Promise species sandbox-breakout PoCproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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