CVE Intelligence
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CVE-2026-25881: @nyariv/sandboxjs host prototype pollution via sandbox escape

SandboxJS versions before 0.8.31 allow sandboxed code to modify host built-in prototypes by passing global prototype references through array literals, which strips the isGlobal protection flag. The record describes this as persistent host-side prototype pollution that may enable remote code execution in applications that use polluted properties in sensitive sinks. The fix is available in 0.8.31.

Published Oct 24, 2026 · Updated Oct 24, 2026 · Ler em português

Overview

SandboxJS is a JavaScript sandboxing library. According to the record, versions before 0.8.31 let sandboxed code bypass the isGlobal protection flag by passing global prototype references, such as Map.prototype, through array literals. This allows direct modification of host built-in prototypes.

Impact

  • Persistent prototype pollution in the host process.
  • The record states this may enable remote code execution in applications that use polluted properties in sensitive sinks.
  • The cited NVD score of 10 reflects high confidentiality, integrity and availability impact.

Affected products and versions

  • Nyariv Sandboxjs before 0.8.31.
  • The fix is included in 0.8.31.

Exploitation status

This CVE is not listed in the CISA KEV catalogue, and no confirmed exploitation in the wild appears in the sources consulted. The SSVC data in the record lists exploitation as none and automatable as no. The advisory reference is tagged Exploit in the record, but that tag does not establish real-world exploitation.

Remediation and mitigation

  • Upgrade SandboxJS to 0.8.31 or later.
  • If an upgrade cannot be applied immediately, follow the vendor advisory mitigation guidance.
  • Reduce exposure by limiting which untrusted code runs inside the sandbox.

Detection guidance

  • Inventory dependencies to identify SandboxJS installations earlier than 0.8.31.
  • Monitor long-running host processes for unexpected changes to built-in prototypes, at a high level.

Limitations of the available information

  • Scores differ by provider: NVD gives 10, GitHub gives 9.1 and another provider gives 9.
  • The record does not describe the vulnerable code path in detail beyond the commit and advisory references.
  • The EPSS date in the record should be verified against the source before relying on it.
  • Whether a specific application is exploitable depends on how it uses polluted properties, which the record does not describe.

Frequently asked questions

Which versions of SandboxJS are affected?

According to the record, versions before 0.8.31 are affected, and the fix is available in 0.8.31.

Is this vulnerability being actively exploited?

This CVE is not listed in the CISA KEV catalogue, and no confirmed exploitation in the wild appears in the sources consulted.

What should administrators do first?

Identify SandboxJS installations and upgrade to 0.8.31 or later. If that is not immediately possible, follow the vendor advisory mitigation guidance.

This analysis was drafted with AI assistance from verified source data and automatically checked against it.