What is the CVSS score of CVE-2026-25586?

CVE-2026-25586 has a CVSS 3.1 base score of 10.0 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H. EPSS exploitation probability: 0.0%.

Which versions of Sandboxjs are affected by CVE-2026-25586?

SandboxJS versions prior to 0.8.29 contain a critical sandbox escape vulnerability (CVSS 10.0) that allows attackers to bypass security controls and execute arbitrary code within sandboxed…. A patch is available.

Is there a public PoC exploit available for CVE-2026-25586?

Yes, a public proof-of-concept exploit is available for CVE-2026-25586. Prioritise patching immediately. EPSS: 0.0%.

How to fix or mitigate CVE-2026-25586?

Within 24 hours: Identify all instances of SandboxJS in use across the organization and their version numbers; communicate findings to development and operations teams. Within 7 days: Upgrade all affected SandboxJS installations to version 0.8.29 or later; test upgraded environments in staging to confirm functionality. Within 30 days: Validate all production deployments have been patched; conduct code review of any sandboxed code execution paths to assess exposure window.

Sandboxjs CVE-2026-25586

CRITICAL

Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') (CWE-74)

2026-02-06 security-advisories@github.com

GHSA-jjpw-65fv-8g48

Information Disclosure Sandboxjs

10.0

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

10.0 CRITICAL

AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 21:54 vuln.today

PoC Detected

Feb 18, 2026 - 14:32 vuln.today

Public exploit code

Patch released

Feb 18, 2026 - 14:32 nvd

Patch available

CVE Published

Feb 06, 2026 - 20:16 nvd

CRITICAL 10.0

DescriptionGitHub Advisory

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.