What is CVE-2026-3990?

CVE-2026-3990 is a medium-severity vulnerability in Cesiumgs Cesiumjs, classified under Cross-site Scripting. CVSS score: 4.3/10. Published 2026-03-12.

How severe is CVE-2026-3990?

Medium severity. CVSS v3 base score is 4.3 out of 10.

RCE in Cesiumgs Cesiumjs

CVE-2026-3990

A security flaw has been discovered in CesiumGS CesiumJS up to 1.137.0. Affected by this issue is some unknown functionality of the file Apps/Sandcastle/standalone.html. The manipulation of the argument c results in cross site scripting. T…

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.000 (13.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N.

Affected products

Cesiumgs Cesiumjs — versions 1.137

Weakness classification (CWE)

References

VDB-350473 | CesiumGS CesiumJS standalone.html cross site scripting (technical-description, vdb-entry)
VDB-350473 | CTI Indicators (IOB, IOC, TTP, IOA) (signature, permissions-required)
Submit #769630 | CesiumGS Cesium <=1.137.0 Cross-Site Scripting (third-party-advisory)
cna@vuldb.com (issue-tracking, exploit)

Frequently asked questions

What is CVE-2026-3990?: CVE-2026-3990 is a medium-severity vulnerability in Cesiumgs Cesiumjs, classified under Cross-site Scripting. CVSS score: 4.3/10. Published 2026-03-12.
How severe is CVE-2026-3990?: Medium severity. CVSS v3 base score is 4.3 out of 10.