VulnerabilityAnalyzed

CVE-2026-25586

This vulnerability is fixed in 0.8.29.

CRITICAL 10.0EPSS 0.65%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.65%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 3.1: 10.0 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
EPSS: 0.65% probability · 49th percentile
CISA KEV: Not listed
Weakness: CWE-74
Affected: nyariv/sandboxjs
Source: security-advisories@github.com

References

https://github.com/nyariv/SandboxJS/commit/67cb186c41c78c51464f70405504e8ef0a6e43c3Patch
https://github.com/nyariv/SandboxJS/security/advisories/GHSA-jjpw-65fv-8g48Exploit, Vendor Advisory
https://github.com/nyariv/SandboxJS/security/advisories/GHSA-jjpw-65fv-8g48Exploit, Vendor Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.