Description
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.
References (2)
Core 2
Core References
Vendor Advisory x_refsource_confirm
https://github.com/nyariv/SandboxJS/security/advisories/GHSA-jjpw-65fv-8g48
Scores
CVSS v3
10.0
EPSS
0.0003
EPSS Percentile
9.7%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CISA SSVC
Vulnrichment
Exploitation
poc
Automatable
yes
Technical Impact
total
Details
CWE
CWE-74
Status
published
Products (2)
nyariv/sandboxjs
< 0.8.29
nyariv/sandboxjs
0 - 0.8.29npm
Published
Feb 06, 2026
Tracked Since
Feb 18, 2026