CVE-2026-34217

SandboxJS has a Sandbox Escape via Prop Object Leak in New Handler

HIGH
7.2
CVSS Score
Published: April 6, 2026 at 03:12 PM UTC
Updated: October 26, 2026 at 10:10 PM UTC
1 product affected across 1 vendorSandboxJS

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Severity
HIGH7.2
Exploit prediction
EPSS 0.3%
SSVC
PoC

Description

SandboxJS is a JavaScript sandboxing library. Prior to 0.8.36, a scope modification vulnerability exists in @nyariv/sandboxjs. The vulnerability allows untrusted sandboxed code to leak internal interpreter objects through the new operator, exposing sandbox scope objects in the scope hierarchy to untrusted code; an unexpected and undesired exploit. While this could allow modifying scopes inside the sandbox, code evaluation remains sandboxed and prototypes remain protected throughout the execution. This vulnerability is fixed in 0.8.36.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.8.36
Affected range stops below 0.8.36, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

x_refsource_CONFIRMExploitMitigationVendor Advisory
Source: cverecord
https://github.com/nyariv/SandboxJS/security/advisories/GHSA-hg73-4w7g-q96w

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-668

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