SEPTEMBER 17, 2026
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Case File

CVE-2026-81900

MEDIUM · CVSS 6.1 EPSS 0.25%

Source: NVD + CISA KEV + EPSS · Published 2026-09-14 · Last synced 2026-09-17

CyberRota Analysis

AI-Generated

Concrete CMS versions prior to 9.5.3 are vulnerable to stored cross-site scripting due to improper handling of YouTube block width and height values, which can allow an attacker with edit_block permissions to inject malicious scripts. This vulnerability can lead to significant security risks, particularly for administrators, as it allows the execution of scripts in the context of users viewing the page. Organizations using affected versions should prioritize patching this vulnerability to mitigate potential exploitation.

CVE
CVE-2026-81900
Severity
MEDIUM
CVSS
6.1
EPSS
0.25%

Original NVD Description

Concrete CMS before 9.5.3 applied only trim() to the YouTube block's stored width and height values and printed them into iframe HTML attributes without escaping or integer casting, resulting in stored cross-site scripting. A user with edit_block permission could inject an event handler that executed script for visitors rendering the page, acting with administrative privileges where the victim was an administrator. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks sh4d0byss for reporting.

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