CVE-2026-25641

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

Published Feb 6, 2026 CVSS 3.1 · 10 Critical EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-7x3h-rm86-3342 @nyariv/sandboxjs vulnerable to sandbox escape via TOCTOU bug on keys in property accesses
History
Type Values Removed Values Added
CPEs cpe:2.3:a:nyariv:sandboxjs:*:*:*:*:*:node.js:*:*
Type Values Removed Values Added
First Time appeared Nyariv
Nyariv sandboxjs
Vendors & Products Nyariv
Nyariv sandboxjs
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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.
Title SandboxJS has a sandbox escape via TOCTOU bug on keys in property accesses
Weaknesses CWE-367
References
Metrics cvssV3_1

{'score': 10, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Feb 6, 2026, 8:20 PM
Reserved
Feb 4, 2026, 5:15 AM
Status
Analyzed
Published
Feb 6, 2026, 8:16 PM
Modified
Jun 17, 2026, 10:24 AM