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TI-2026-20741 Aliases CVE-2026-25641GHSA-7x3h-rm86-3342

SandboxJS has a sandbox escape via TOCTOU bug on keys in property accesses

Priority HIGH 82CWE-367Published · 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, there is a sandbox escape vulnerability due to a mismatch between the key on which the validation is performed and the key used for accessing properties. Even though the key used in property accesses is annotated as string, this is never enforced. So, attackers can pass malicious objects that coerce to different string values when used, e.g., one for the time the key is sanitized using hasOwnProperty(key) and a different one for when the key is used for the actual property access. This vulnerability is fixed in 0.8.29.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00521 44th 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-7x3h-rm86-3342
  • 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-7x3h-rm86-3342

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-7x3h-rm86-3342 @nyariv/sandboxjs (npm) Fixed in 0.8.29 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-25641
  2. 2026-10-03 Alias added: GHSA-7x3h-rm86-3342

References

Exploit 1

Patch 1

Advisory 1

Other 2

  • 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-2026-20694 SandboxJS has a Sandbox Escape CVSS 3.1CRITICAL 10.0
  • TI-2026-20693 SandboxJS has a Sandbox Escape via Prototype Whitelist Bypass and Host Prototype Pollution 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