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High 7.5Published Sep 15, 2026

CVE-2026-18113Concrete CMS 9.0 to 9.5.2 is vulnerable to Stored XSS in the Top Navigation Bar Block via Dropdown Child Page Names

Updated under an hour ago ()

Does this affect you?

It affects Concrete CMS. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

In Concrete CMS 9.0 to 9.5.2, the Top Navigation Bar block did not HTML-escape dropdown child page names before writing them into the page, so a user who could create or rename pages could store a script through a child page name and have it run in the browser of any visitor, editor, or administrator who viewed the navigation and opened the affected dropdown. In the Concrete CMS origin, the script executed with the victim's privileges and could read same-origin content or perform actions available to that user. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.5 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks labixiaoxin97 for reporting.

CVSS
7.5 HIGH (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Weakness (CWE)
CWE-79
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
ConcreteCMS
NVD analysis
Awaiting Analysis
Record last updated
Sep 20, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
Concrete CMS Concrete CMS
concrete_cms:concrete_cms (from the name)
from 9.0.0 through 9.5.2
CNA record

References

  • release-notes

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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