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CVE-2026-81901

8.7, high

Concrete CMS Missing Authorization Vulnerability

NVD (opens in a new tab) CVE.org (opens in a new tab)
CVSS
8.7, high high CVSS v3.1
EPSS, next 30 days
0.4% higher than 30.7% of scored CVEs
Exploitation
No public evidence
Published
14 Sept 2026a month ago

Description

In Concrete CMS 9.2.0 through 9.5.2, the REST API page update endpoint (PUT /ccm/api/1.0/pages/{cID}) did not enforce page-property, page-template, or page-type authorization. A user granted only content-editing rights on a page could therefore alter its properties, template, and type through the API, and could set the header_extra_content attribute, which is rendered unescaped into the head element of every page, to persist JavaScript that executed in the browser of every visitor, including higher-privileged reviewers who approve the page version. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.2 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori from Tenzai for reporting.

Details

Vendor
Concrete CMS
Product
Concrete CMS
Weakness
CWE-862 (opens in a new tab)
Status
Analyzed
Updated
18 Sept 2026
Assigner
ff5b8ace-8b95-4078-9743-eac1ca5451de

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

References 1

Other references 1

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other Concrete CMS CVEs

Every Concrete CMS CVE we hold

Same vendor in what we hold, not a known link between the flaws.

  • CVE-2026-85385 Concrete CMS Cross-Site Scripting Vulnerability EPSS 0.5% 9.6, critical
  • CVE-2026-85387 Concrete CMS Insufficient Session Expiration Vulnerability EPSS 0.3% 7.1, high
  • CVE-2026-18110 Concrete CMS Missing Authorization Vulnerability EPSS 0.3% 7.5, high
  • CVE-2026-81895 Concrete CMS SQL Injection Vulnerability EPSS 0.5% 7.2, high
  • CVE-2026-18423 Concrete CMS Authorization Bypass Through User-Controlled Key Vulnerability EPSS 0.2% 7.1, high
  • CVE-2026-18424 Concrete CMS Server-Side Request Forgery Vulnerability EPSS 0.2% 7.1, high
  • CVE-2026-18119 Concrete CMS Cross-Site Scripting Vulnerability EPSS 0.3% 9, critical
  • CVE-2026-81902 Concrete CMS Cross-Site Request Forgery Vulnerability EPSS 0.2% 8.1, high

Beyond this page

Is CVE-2026-81901 in your network?

This page tells you how dangerous CVE-2026-81901 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

  • EXYS7600 OCELOT

    Find it before attackers do

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  • EXYS7950 KONDRA

    Detect it if it's exploited

    Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.

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Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 17 Oct 2026, not the live upstream state.