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Vulnerabilities

Vulnerability · CVE-2026-25520

SandboxJS is a JavaScript sandboxing library.

Published Feb 6, 2026 · catalog updated Feb 6, 2026 · SandboxJS is a JavaScript

Last checked Nov 7, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-25520. EPSS is 0.85%. Act only if a listed version of SandboxJS is a JavaScript is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (SandboxJS is a JavaScript).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Critical10.0
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.85%
Remediation
Version ranges on file
Affected products
vendor nyariv sandboxjs < 0.8.29

SandboxJS is a JavaScript sandboxing library. Prior to 0.8.29, The return values of functions aren't wrapped. Object.values/Object.entries can be used to get an Array containing the host's Function constructor, by using Array.prototype.at you can obtain the hosts Function constructor, which can be used to execute arbitrary code outside of the sandbox. This vulnerability is fixed in 0.8.29.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor nyariv sandboxjs < 0.8.29< 0.8.29

How to fix CVE-2026-25520

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-25520. EPSS is 0.85%. Act only if a listed version of SandboxJS is a JavaScript is installed.

Which versions are affected?

Compare what you have installed with nyariv sandboxjs < 0.8.29 < 0.8.29. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.85%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Feb 6, 2026 · EUVD

    Detected

    SandboxJS is a JavaScript sandboxing library. Prior to 0.8.29, The return values of functions aren't wrapped. Object.values/Object.entries can be used to get an Array containing the host's Function constructor, by using Array.prototype.at you can obtain the hosts Function constructor, which can be used to execute arbitrary code outside of the sandbox. This vulnerability is fixed in 0.8.29.

  2. Feb 6, 2026 · EUVD

    Updated

    SandboxJS is a JavaScript sandboxing library. Prior to 0.8.29, The return values of functions aren't wrapped. Object.values/Object.entries can be used to get an Array containing the host's Function constructor, by using Array.prototype.at you can obtain the hosts Function constructor, which can be used to execute arbitrary code outside of the sandbox. This vulnerability is fixed in 0.8.29.

Sources

  • CVE.orgVulnerability recordCVE-2026-25520

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-25520

    30-day exploitation probability 0.85%

    first.org
  • EUVDVulnerability recordEUVD-2026-5591

    SandboxJS is a JavaScript sandboxing library. Prior to 0.8.29, The return values of functions aren't wrapped. Object.values/Object.entries can be used to get an Array containing the host's Function constructor, by using Array.prototype.at you can obtain the hosts Function constru

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Nov 7, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 7, 2026
  • CVE.orgNov 4, 2026
  • EUVDNov 3, 2026