Cyber Resilience

CVE-2026-25142

RCE in Nyariv Sandboxjs ≤ 0.8.27

Public PoCRCE
Published
02 February 2026
Modified
18 February 2026
Patch / advisory
CVSS Score v3.1 10.0
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
EPSS Score 0.011 62th percentile
Risk Priority 76 floored blend · peak EPSS

Summary

CVE-2026-25142 is a critical-severity Code Injection (CWE-94) vulnerability in Nyariv Sandboxjs. Its CVSS base score is 10.0 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Command and Scripting Interpreter (T1059); ranked in the top 38% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-25142 affects SandboxJS, a JavaScript sandboxing library, in versions prior to 0.8.27. The vulnerability stems from improper restrictions on the __lookupGetter__ function, which allows attackers to access prototypes and escape the sandbox, potentially leading to remote code execution. This issue is classified under CWE-94 (Improper Control of Generation of Code) and CWE-1321 (Improperly Controlled Modification of Object Prototype Attributes), with a maximum CVSS v3.1 score of 10.0 (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H), indicating critical severity due to its network accessibility and high impact across confidentiality, integrity, and availability.

Any remote attacker can exploit this vulnerability without authentication, privileges, or user interaction by leveraging the unrestricted __lookupGetter__ to retrieve prototypes and bypass sandbox boundaries. Successful exploitation enables full sandbox escape, granting attackers the ability to execute arbitrary code in the context of the hosting application, potentially compromising the entire system.

The GitHub security advisory (GHSA-9p4w-fq8m-2hp7) and associated commit (75c8009db32e6829b0ad92ca13bf458178442bd3) detail the fix implemented in version 0.8.27, which properly restricts prototype access in the executor module (src/executor.ts lines 368-398). Security practitioners should update to SandboxJS 0.8.27 or later to mitigate this issue.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

SandboxJS is a JavaScript sandboxing library. Prior to 0.8.27, SanboxJS does not properly restrict __lookupGetter__ which can be used to obtain prototypes, which can be used for escaping the sandbox / remote code execution. This vulnerability is fixed in 0.8.27.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1059 Command and Scripting Interpreter Execution
Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries.
T1059.001 PowerShell Execution
Adversaries may abuse PowerShell commands and scripts for execution.
T1059.002 AppleScript Execution
Adversaries may abuse AppleScript for execution.
T1059.004 Unix Shell Execution
Adversaries may abuse Unix shell commands and scripts for execution.
T1059.005 Visual Basic Execution
Adversaries may abuse Visual Basic (VB) for execution.
T1059.006 Python Execution
Adversaries may abuse Python commands and scripts for execution.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-26954Same product: Nyariv Sandboxjs
CVE-2026-43898Same product: Nyariv Sandboxjs
CVE-2026-25587Same product: Nyariv Sandboxjs
CVE-2026-25881Same product: Nyariv Sandboxjs
CVE-2026-23830Same product: Nyariv Sandboxjs
CVE-2026-2964Shared CWE-1321, CWE-94
CVE-2026-15195Shared CWE-1321, CWE-94
CVE-2026-6621Shared CWE-1321, CWE-94
CVE-2026-16151Shared CWE-1321, CWE-94
CVE-2026-55388Shared CWE-1321, CWE-94

Affected Assets

nyariv
sandboxjs
≤ 0.8.27

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V15.3.6
  • V1.3.1

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation finds code paths that accept and execute externally influenced strings.

Input validation directly stops untrusted data from being used to construct executable code without neutralization.

Least privilege limits the damage an injected code fragment can perform once executed.

Requiring documented secure development standards and tools enforces use of safe code-generation APIs and escaping.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

PR.PS-06's SDLC practices directly target injection flaws via secure coding and testing (mostly), yet as a single broad outcome it leaves many code-generation specifics unaddressed (partial).

PR.DS-10 none match
prevents

PR.DS-10 protects runtime data confidentiality/integrity but has no bearing on neutralizing externally influenced input during code generation, so neither direction shows any preventive effect.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing in development catches prototype-pollution flaws before release.

prevents

Secure development lifecycle mandates input validation and object-handling controls that directly prevent prototype pollution.

prevents

Application security requirements explicitly call for safeguards against unsafe object attribute manipulation.

prevents

Secure architecture principles reduce the likelihood of prototype pollution through safe design patterns.

prevents

Banning unapproved code samples and unauthenticated web services, combined with secure-coding standards and SAST, prevents the dynamic generation or inclusion of attacker-supplied code.

prevents

Change-management processes ensure security fixes for prototype-pollution issues are tracked and deployed.

References