Sandbox escape via host prototype pollution in SandboxJS (< 0.8.31)
SandboxJS (the @nyariv/sandboxjs JavaScript sandboxing library) contains a sandbox escape in versions prior to 0.8.31 where the library’s global-object protection mechanism (an isGlobal taint/flag intended to prevent writes to host/system objects) can be bypassed. By placing a protected global prototype reference (e.g., Map.prototype / Set.prototype) into an array literal and then retrieving it, the isGlobal protection is stripped (“laundered” through the array intermediary). The attacker can then directly mutate host built-in prototypes from within the sandbox, resulting in persistent host-side prototype pollution. This can become RCE in the embedding application when polluted properties are later consumed by sensitive sinks (example gadget: execSync(obj.cmd)). Fixed in 0.8.31.
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Impact, mitigation & remediation
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
If you can’t patch tonight, do this now.
exec/execSync/spawn, dynamic require, eval) and avoid using attacker-influenced properties.Remediation
Patch, then assume compromise.
isGlobal protection across array operations and blocks writes to built-in prototypes obtained indirectly (per the referenced fix commit).Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Affected products & vendors
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Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
12 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Unknown (listed as a trending CVE for SandboxJS without details in the provided content).
A critical SandboxJS sandbox-escape issue where global prototype references (e.g., Map.prototype/Set.prototype) lose a protection/taint flag when placed into and retrieved from an array, enabling prototype pollution of host-side built-ins and potentially leading to application-dependent remote code execution.
Unknown (only referenced as a critical SandboxJS flaw enabling host takeover; no technical details provided in the content).
A critical SandboxJS sandbox-escape flaw where the library’s isGlobal protection/taint tracking can be stripped by passing protected global prototype references through an array literal, enabling host-side prototype mutation (prototype pollution) and potentially RCE via polluted properties used in sensitive sinks (e.g., execSync).
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.