CesiumGS CesiumJS up to 1.137.0 standalone.html c cross site scripting ⚔ [Disputed]
Summary
A vulnerability marked as problematic has been reported in CesiumGS CesiumJS up to 1.137.0. This affects an unknown part of the file Apps/Sandcastle/standalone.html. This manipulation of the argument c causes cross site scripting. This vulnerability appears as CVE-2026-3990. The attack may be initiated remotely. In addition, an exploit is available. There are still doubts about whether this vulnerability truly exists. The vendor was contacted early about this disclosure but did not respond in any way. According to CVE-2023-48094, "the vendor's position is that Apps/Sandcastle/standalone.html is part of the CesiumGS/cesium GitHub repository, but is demo code that is not part of the CesiumJS JavaScript library product."
Details
A vulnerability has been found in CesiumGS CesiumJS up to 1.137.0 and classified as problematic. Affected by this vulnerability is an unknown code of the file Apps/Sandcastle/standalone.html. The manipulation of the argument c with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. As an impact it is known to affect integrity.
The advisory is shared at github.com. This vulnerability is known as CVE-2026-3990. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Technical details and also a public exploit are known. MITRE ATT&CK project uses the attack technique T1059.007 for this issue.
It is possible to download the exploit at github.com. It is declared as proof-of-concept. The real existence of this vulnerability is still doubted at the moment. The vendor was contacted early about this disclosure but did not respond in any way. According to CVE-2023-48094, "the vendor's position is that Apps/Sandcastle/standalone.html is part of the CesiumGS/cesium GitHub repository, but is demo code that is not part of the CesiumJS JavaScript library product." By approaching the search of inurl:Apps/Sandcastle/standalone.html it is possible to find vulnerable targets with Google Hacking.
There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.
The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-11534). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Product
Vendor
Name
Version
CPE 2.3
CPE 2.2
CVSSv4
VulDB Vector: 🔒VulDB Reliability: 🔍
CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒
CVSSv3
VulDB Meta Base Score: 4.3VulDB Meta Temp Score: 4.1
VulDB Base Score: 4.3
VulDB Temp Score: 3.9
VulDB Vector: 🔒
VulDB Reliability: 🔍
CNA Base Score: 4.3
CNA Vector: 🔒
CVSSv2
| AV | AC | Au | C | I | A |
|---|---|---|---|---|---|
| 💳 | 💳 | 💳 | 💳 | 💳 | 💳 |
| 💳 | 💳 | 💳 | 💳 | 💳 | 💳 |
| 💳 | 💳 | 💳 | 💳 | 💳 | 💳 |
| Vector | Complexity | Authentication | Confidentiality | Integrity | Availability |
|---|---|---|---|---|---|
| Unlock | Unlock | Unlock | Unlock | Unlock | Unlock |
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍
Exploiting
Class: Cross site scriptingCWE: CWE-79 / CWE-94 / CWE-74
CAPEC: 🔒
ATT&CK: 🔒
Physical: No
Local: No
Remote: Yes
Availability: 🔒
Access: Public
Status: Proof-of-Concept
Download: 🔒
Google Hack: 🔒
EPSS Score: 🔒
EPSS Percentile: 🔒
Price Prediction: 🔍
Current Price Estimation: 🔒
| 0-Day | Unlock | Unlock | Unlock | Unlock |
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| Today | Unlock | Unlock | Unlock | Unlock |
Threat Intelligence
Interest: 🔍Active Actors: 🔍
Active APT Groups: 🔍
Countermeasures
Recommended: no mitigation knownStatus: 🔍
0-Day Time: 🔒
Timeline
03/11/2026 Advisory disclosed03/11/2026 VulDB entry created
03/17/2026 VulDB entry last update
Sources
Advisory: github.comStatus: Not defined
Disputed: 🔍
CVE: CVE-2026-3990 (🔒)
GCVE (CVE): GCVE-0-2026-3990
GCVE (VulDB): GCVE-100-350473
EUVD: 🔒
scip Labs: https://www.scip.ch/en/?labs.20161013
Entry
Created: 03/11/2026 17:54Updated: 03/17/2026 10:08
Changes: 03/11/2026 17:54 (57), 03/12/2026 12:18 (1), 03/17/2026 10:08 (31)
Complete: 🔍
Submitter: Ana10gy
Cache ID: 216::103
Submit
Accepted
- Submit #769630: CesiumGS Cesium <=1.137.0 Cross-Site Scripting (by Ana10gy)
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
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