CVE-2026-25641Public exploitNetwork attack vector

Host code execution via mutable property-key coercion

Published Feb 6, 2026 · Updated Feb 6, 2026

Sandbox escape in nyariv SandboxJS before 0.8.29 allows attackers to execute arbitrary host JavaScript through a crafted property key. Property access in executor.ts calls hasOwnProperty on a key object and then coerces that object again for access, allowing its toString result to change to proto. Exploitation requires an application to let the attacker run code inside the sandbox; escape exposes the host runtime and permits arbitrary commands.

CVSS severity10.0
Critical
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Sandbox escape in nyariv SandboxJS before 0.8.29 allows attackers to execute arbitrary host JavaScript through a crafted property key. Property access in executor.ts calls hasOwnProperty on a key object and then coerces that object again for access, allowing its toString result to change to proto. Exploitation requires an application to let the attacker run code inside the sandbox; escape exposes the host runtime and permits arbitrary commands.

The record

CVE
CVE-2026-25641
Published
Feb 6, 2026
Updated
Feb 6, 2026
Vendor
nyariv
Product
SandboxJS
Classifications
CWE-367, CWE-74, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 6, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 6, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=< 0.8.29

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

nyariv · SandboxJSversion=< 0.8.29

Published CVSS scores

9.0NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
10.0GitHubCVSS: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-367Time-of-check Time-of-use (TOCTOU) Race Condition
CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
T1203Exploitation for Client Execution

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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