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CVE-2026-25881

Nyariv Sandboxjs vulnerability

9.0 CRITICALPublic exploitEPSS 0.73%
  1. Published9 Feb 2026

Description

SandboxJS is a JavaScript sandboxing library. Prior to 0.8.31, a sandbox escape vulnerability allows sandboxed code to mutate host built-in prototypes by laundering the isGlobal protection flag through array literal intermediaries. When a global prototype reference (e.g., Map.prototype, Set.prototype) is placed into an array and retrieved, the isGlobal taint is stripped, permitting direct prototype mutation from within the sandbox. This results in persistent host-side prototype pollution and may enable RCE in applications that use polluted properties in sensitive sinks (example gadget: execSync(obj.cmd)). This vulnerability is fixed in 0.8.31.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityHigh
Privileges requiredNone
User interactionNone
ScopeChanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Affected products

Nyariv Sandboxjs< 0.8.31

Remediation

Fixed in
Nyariv Sandboxjs≥ 0.8.31

References

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Frequently asked

Is CVE-2026-25881 being actively exploited?

CVE-2026-25881 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.73%.

How severe is CVE-2026-25881?

CVE-2026-25881 has a CVSS 3.1 base score of 9.0, rated critical. EPSS estimates a 0.73% probability of exploitation.

Which products are affected by CVE-2026-25881?

Affected products include Nyariv Sandboxjs.

How do I fix CVE-2026-25881?

Upgrade affected software to a fixed version, for example Nyariv Sandboxjs 0.8.31 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-25881 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.