CVE-2026-8139
Stored XSS in Concrete CMS via External-Link Page
Publication date: 2026-05-21
Last updated on: 2026-05-21
Assigner: ConcreteCMS
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| concrete_cms | concrete_cms | to 9.5.1 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| 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. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability affects Concrete CMS version 9.5.0 and below. It is a Stored Cross-Site Scripting (XSS) issue that occurs via the external-link page parameter named cvName. The problem arises because the function updateCollectionAliasExternal does not properly sanitize input, allowing malicious scripts to be stored and later executed in users' browsers.
How can this vulnerability impact me? :
The vulnerability can allow attackers to inject malicious scripts into the website that will be stored and executed when other users visit the affected pages. This can lead to unauthorized actions performed on behalf of users, theft of sensitive information, or other malicious activities. However, the CVSS score of 2.0 indicates a relatively low severity, suggesting limited impact under certain conditions.