CVE-2026-34217
published 2026-04-06CVE-2026-34217: SandboxJS is a JavaScript sandboxing library. Prior to 0.8.36, a scope modification vulnerability exists in @nyariv/sandboxjs. The vulnerability allows…
PriorityP344high7.2CVSS 3.1
AVNACLPRNUINSCCLILAN
EPSS
0.29%
20.9th percentile
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
2 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| nyariv | sandboxjs | < 0.8.36 | 0.8.36 |
| nyariv | sandboxjs | >= 0 < 0.8.36 | 0.8.36 |
CVSS provenance
nvdv3.17.2HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
nvdv4.06.9MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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OSV
SandboxJS: Sandbox Escape via Prop Object Leak in New Handler
osv·2026-04-03
CVE-2026-34217 [MEDIUM] SandboxJS: Sandbox Escape via Prop Object Leak in New Handler
SandboxJS: Sandbox Escape via Prop Object Leak in New Handler
## Description
A scope modification vulnerability exists in `@nyariv/sandboxjs` version 0.8.35 and below. 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.
## Vulnerable Code Location
### Primary: The `New` Operator Handler
**File**: `src/executor.ts`, lines 1275–1280
```typescript
addOps unknown, unknown[]>(
LispType.New,
({ done, a, b, context }) => {
if (!context.ctx.globalsWhitelist.has(a) && !cont
GHSA
SandboxJS: Sandbox Escape via Prop Object Leak in New Handler
ghsa·2026-04-03
CVE-2026-34217 [MEDIUM] CWE-668 SandboxJS: Sandbox Escape via Prop Object Leak in New Handler
SandboxJS: Sandbox Escape via Prop Object Leak in New Handler
## Description
A scope modification vulnerability exists in `@nyariv/sandboxjs` version 0.8.35 and below. 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.
## Vulnerable Code Location
### Primary: The `New` Operator Handler
**File**: `src/executor.ts`, lines 1275–1280
```typescript
addOps unknown, unknown[]>(
LispType.New,
({ done, a, b, context }) => {
if (!context.ctx.globalsWhitelist.has(a) && !cont
No detection rules found.
No public exploits indexed.
2026-04-06
Published