CVE-2026-25586 | SandboxJS is a JavaScript sandboxing library. Prior to 0.8.2… | CVSS 10.0 CRITICAL

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.

Metadata

CVE ID: CVE-2026-25586
State: PUBLISHED
Assigner: GitHub_M
Reserved: 2026-02-03 01:02 UTC
Published: 2026-02-06 19:54 UTC
Last updated: 2026-02-06 20:17 UTC
Primary CWE: CWE-74
CWE-74: Improper Neutralization of Special Elements in Outpu…
Vendor / Product: nyariv / SandboxJS
Sources: cve.org · NVD

Severity & Metrics

10.0 CRITICAL CVSS 3.1

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

SSVC — CISA Coordinator

Exploitation: PoC
Automatable: yes
Tech. Impact: total

Affected products (1)

Vendor	Product	Platform	Versions
nyariv	SandboxJS	—	< 0.8.29

Weakness (CWE)

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

CVSS scores (1)

Score	Severity	Version	Source	Vector
10.0	CRITICAL	3.1	cna	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

References (2)

https://github.com/nyariv/SandboxJS/security/advisories/GHSA-jjpw-65fv-8g48 https://github.com/nyariv/SandboxJS/security/advisories/GHSA-jjpw-65fv-8g48
https://github.com/nyariv/SandboxJS/commit/67cb186c41c78c51464f70405504e8ef0a6e43c3 https://github.com/nyariv/SandboxJS/commit/67cb186c41c78c51464f70405504e8ef0a6e43c3