Cross-Site Scripting Flaw in CesiumJS by CesiumGS
CVE-2026-3990

5.3MEDIUM

Key Information:

Vendor

Cesiumgs

Status
Cesiumjs
Vendor
CVE Published:
12 March 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-3990?

A security vulnerability has been identified in CesiumGS's CesiumJS, specifically in the demo code located in Apps/Sandcastle/standalone.html. This flaw allows for the manipulation of parameters leading to cross-site scripting (XSS) attacks, which can be executed remotely. This exploitation can potentially compromise user data and application integrity. Despite attempts to notify the vendor about this issue, no response has been received. It is essential for users and developers utilizing vulnerable versions of CesiumJS to implement necessary security measures to mitigate potential attacks.

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Affected Version(s)

CesiumJS 1.137

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-3990 - Proof of Concept

References

https://vuldb.com/?id.350473
vdb-entrytechnical-description
https://vuldb.com/?ctiid.350473
signaturepermissions-required
https://vuldb.com/?submit.769630
third-party-advisory

CVSS V4

Score:
5.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Ana10gy (VulDB User)
VulDB
JSON
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