SEPTEMBER 19, 2026
Live Feed
Back to database
Case File

CVE-2026-81927

MEDIUM · CVSS 5.4 EPSS 0.31%

Source: NVD + CISA KEV + EPSS · Published 2026-09-15 · Last synced 2026-09-18

CyberRota Analysis

AI-Generated

Concrete CMS versions prior to 9.5.3 are vulnerable to a stored cross-site scripting (XSS) issue in SVG file handling, specifically when the SVG processing is configured to reject potentially harmful elements. This flaw allows an attacker to upload SVG files containing malicious JavaScript, which can then execute in the browsers of users who view the affected files. Organizations using Concrete CMS should prioritize this vulnerability, especially those allowing user-uploaded content, to mitigate potential exploitation risks.

CVE
CVE-2026-81927
Severity
MEDIUM
CVSS
5.4
EPSS
0.31%
Java

Original NVD Description

Concrete CMS before 9.5.3 contained a stored cross-site scripting vulnerability in SVG file handling. When SVG processing was set to the non-default "Reject files containing potentially harmful elements" mode (concrete.file_manager.images.svg_sanitization.action = reject), uploaded SVGs were checked only against a small built-in blocklist covering the script element and on* event-handler attributes; the broader enshrined/svg-sanitize pass still ran, but its result was discarded, so vectors it would have stripped, such as a javascript: URI in an xlink:href, were stored unmodified and executed when the file was opened directly. A user able to upload files could thereby run arbitrary JavaScript in the browser of any user who viewed the file. The default sanitize mode was not affected. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 1.8 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Oriol Ortiz for reporting.

Related CVEs

Other vulnerabilities affecting the same vendor(s)