SEPTEMBER 14, 2026
Live Feed
Back to database
Case File

CVE-2026-81917

MEDIUM · CVSS 5.1 EPSS 0.31% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-09-11 · Last synced 2026-09-14

CyberRota Analysis

AI-Generated

Concrete CMS versions prior to 9.5.3 are vulnerable due to inadequate HTML output escaping in the Document Library block, allowing users with file editing permissions to inject malicious scripts into the file description and tags fields. This could lead to cross-site scripting (XSS) attacks, enabling unauthorized access to session data or actions executed in the context of any visitor, including those who are unauthenticated. Organizations using affected versions should prioritize applying the latest updates to mitigate potential exploitation risks.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Detected Signals
exploit

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-81917
Severity
MEDIUM
CVSS
5.1
EPSS
0.31%

Original NVD Description

Concrete CMS below 9.5.3 does not apply HTML output escaping to the file description and tags fields when rendering the Document Library block, so a user with permission to edit file properties could store a script payload that executed in the browser of any visitor to a page displaying the block with the description or tags column enabled, including unauthenticated visitors. Successful exploitation could allow theft of session data or actions performed in the visitor's context. The block controller returned the description and tags values without the h() escaping already applied to the title column, and the block view template wrote the returned value directly into the results table The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 5.1 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N. Thanks Nguyen Manh Thuan for reporting.