Host code execution via function-property prototype bypass
Published Feb 2, 2026 · Updated Feb 2, 2026
Code injection in nyariv SandboxJS before 0.8.27 allows remote attackers to escape the JavaScript sandbox and execute host code. The function-property access branch in executor.ts skips prototype-chain whitelist checks, exposing Object.prototype.lookupGetter to sandboxed code. Untrusted JavaScript execution is required; the exposed getter recovers host prototypes and the Function constructor, enabling arbitrary host commands.
Summary
What happened
Code injection in nyariv SandboxJS before 0.8.27 allows remote attackers to escape the JavaScript sandbox and execute host code. The function-property access branch in executor.ts skips prototype-chain whitelist checks, exposing Object.prototype.lookupGetter to sandboxed code. Untrusted JavaScript execution is required; the exposed getter recovers host prototypes and the Function constructor, enabling arbitrary host commands.
The record
- CVE
- CVE-2026-25142
- Published
- Feb 2, 2026
- Updated
- Feb 2, 2026
- Vendor
- nyariv
- Product
- SandboxJS
- Classifications
- CWE-1321, CWE-94, T1059.007
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 2, 2026CVE publishedPublication date reported by the CVE source.
- Feb 2, 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=< 0.8.27
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
- GitHub advisory 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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