What is CVE-2026-25520?

CVE-2026-25520 is a critical-severity vulnerability in Nyariv Sandboxjs, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 10.0/10. Published 2026-02-06.

How severe is CVE-2026-25520?

Critical severity. CVSS v3 base score is 10.0 out of 10.

Vulnerability in Nyariv Sandboxjs

CVE-2026-25520

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…

EPSS: 0.001 (17.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

Affected products

Nyariv Sandboxjs — versions < 0.8.29

Weakness classification (CWE)

CWE-74 — Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection)

References

https://github.com/nyariv/SandboxJS/security/advisories/GHSA-58jh-xv4v-pcx4 (x_refsource_CONFIRM)
https://github.com/nyariv/SandboxJS/commit/67cb186c41c78c51464f70405504e8ef0a6e43c3 (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-25520?: CVE-2026-25520 is a critical-severity vulnerability in Nyariv Sandboxjs, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 10.0/10. Published 2026-02-06.
How severe is CVE-2026-25520?: Critical severity. CVSS v3 base score is 10.0 out of 10.