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TI-2026-20693 Aliases CVE-2026-25586GHSA-jjpw-65fv-8g48

SandboxJS has a Sandbox Escape via Prototype Whitelist Bypass and Host Prototype Pollution

Priority HIGH 82CWE-74Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub.

Summary

SandboxJS is a JavaScript sandboxing library. Prior to 0.8.29, a sandbox escape is possible by shadowing hasOwnProperty on a sandbox object, which disables prototype whitelist enforcement in the property-access path. This permits direct access to __proto__ and other blocked prototype properties, enabling host Object.prototype pollution and persistent cross-sandbox impact. This vulnerability is fixed in 0.8.29.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00692 53rd percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed SandboxJS (nyariv): 0.8.29@nyariv/sandboxjs (npm): 0.8.29

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
nyarivSandboxJSbefore 0.8.290.8.29Patch availableCNA
—@nyariv/sandboxjs (npm)before 0.8.290.8.29Patch availableGHSA-jjpw-65fv-8g48
  • SandboxJS Vendornyariv Affected before 0.8.29 Fixed in 0.8.29 Patch available CNA
  • @nyariv/sandboxjs (npm) Vendor— Affected before 0.8.29 Fixed in 0.8.29 Patch available GHSA-jjpw-65fv-8g48

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:nyariv:sandboxjs:*:*:*:*:*:node.js:*:*before 0.8.29Vulnerablenyariv
  • cpe:2.3:a:nyariv:sandboxjs:*:*:*:*:*:node.js:*:* Versions before 0.8.29 Vulnerable ·nyariv

Remediation

  • Fix · CNA SandboxJS (nyariv) Fixed in 0.8.29
  • Fix · GHSA-jjpw-65fv-8g48 @nyariv/sandboxjs (npm) Fixed in 0.8.29 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-25586
  2. 2026-10-03 Alias added: GHSA-jjpw-65fv-8g48

References

Exploit 1

Patch 1

Advisory 1

Other 1

  • TI-2026-31962 SandboxJS: Sandbox escape via Function.caller leakage of internal call op CVSS 3.1CRITICAL 10.0
  • TI-2026-26503 SandboxJS: Sandbox integrity escape CVSS 3.1CRITICAL 10.0
  • TI-2026-21440 SandboxJS has a Sandbox Escape CVSS 3.1CRITICAL 10.0
  • TI-2026-20741 SandboxJS has a sandbox escape via TOCTOU bug on keys in property accesses CVSS 3.1CRITICAL 10.0
  • TI-2026-20694 SandboxJS has a Sandbox Escape CVSS 3.1CRITICAL 10.0
  • TI-2026-20629 SandboxJS has a Sandbox Escape CVSS 3.1CRITICAL 10.0
See all 12 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences