CVE-2026-26954Public exploitNetwork attack vector

Arbitrary code execution via leaked Function arrays

Published Mar 13, 2026 · Updated Mar 13, 2026

Code injection in nyariv SandboxJS before 0.8.34 allows remote attackers to execute arbitrary host JavaScript through sandboxed code. The sandbox exposes Function values through array-producing Object.entries, Object.values, slice, and at operations, and Object.fromEntries then assigns Function to an attacker-chosen constructible property. Reachability requires a consuming application to execute attacker-controlled JavaScript; escape grants that code the host process's permissions.

CVSS severity10.0
Critical
EPSS probability0.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in nyariv SandboxJS before 0.8.34 allows remote attackers to execute arbitrary host JavaScript through sandboxed code. The sandbox exposes Function values through array-producing Object.entries, Object.values, slice, and at operations, and Object.fromEntries then assigns Function to an attacker-chosen constructible property. Reachability requires a consuming application to execute attacker-controlled JavaScript; escape grants that code the host process's permissions.

The record

CVE
CVE-2026-26954
Published
Mar 13, 2026
Updated
Mar 13, 2026
Vendor
nyariv
Product
SandboxJS
Classifications
CWE-94, T1059.007
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.8.34

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

nyariv · SandboxJSversion=< 0.8.34

Published CVSS scores

10.0GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
T1059.007Command and Scripting Interpreter: JavaScript

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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