TI-2026-07348 Aliases CVE-2026-8353 GHSA-q9fm-mpg8-8jqm

Concrete CMS version 9.0 to 9.5.0 is vulnerable to Stored XSS via page name in atomik theme

LOW 10CWE-79Published 2026-05-22 · Updated 2026-05-22

Key facts

Attack vector: Network
Privileges required: High
User interaction: None
Attack complexity: Low
Attack requirements: Present
Impact type: Cross-site scripting
Confidentiality · integrity · availability: Low · Low · None
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-79.

Summary

Concrete CMS version 9.0 to 9.5.0 is vulnerable to Stored XSS via page name in the Atomik theme. A rogue editor can inject arbitrary JavaScript that executes in the context of any authenticated user visiting the affected account pages. This can lead to session hijacking, credential theft, malicious actions performed on behalf of users, and potential privilege escalation. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 2.1 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori (Tenzai) for reporting.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00149 4th percentileScored 2026-11-07

Fix Fixed concrete5/concrete5 (Packagist): 9.5.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
—	concrete5/concrete5 (Packagist)	9.0.0RC.1 to before 9.5.1	9.5.1	Patch available	GHSA-q9fm-mpg8-8jqm

concrete5/concrete5 (Packagist) Vendor— Affected 9.0.0RC.1 to before 9.5.1 Fixed in 9.5.1 Patch available GHSA-q9fm-mpg8-8jqm

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:concretecms:concrete_cms::::::::	9.0 to before 9.5.1	Vulnerable	Concrete CMS

cpe:2.3:a:concretecms:concrete_cms:*:*:*:*:*:*:*:* Versions 9.0 to before 9.5.1 Vulnerable ·Concrete CMS

Remediation

Fix · GHSA-q9fm-mpg8-8jqm concrete5/concrete5 (Packagist) Fixed in 9.5.1 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-8353
2026-10-03 Alias added: GHSA-q9fm-mpg8-8jqm

References

Advisory 2

Other 1

https://github.com/concretecms/concretecms

TI-2026-23602 ConcreteCMS v9.4.7 contains a Denial of Service (DoS) vulnerability in the File Manager… CVSS 3.1MEDIUM 6.5
TI-2023-23992 A Cross Site Scripting (XSS) vulnerability in Concrete CMS from versions 9.2.0 to 9.2.2… CVSS 3.1MEDIUM 5.4
TI-2023-26495 Concrete CMS before 8.5.13 and 9.x before 9.2.2 allows unauthorized access because… CVSS 3.1CRITICAL 9.8
TI-2026-14907 Missing authorization in Concrete CMS CVSS 4.0HIGH 8.7
TI-2022-06200 Cleartext transmission of sensitive information in https://github.com/concrete5/concrete5 CVSS 3.1CRITICAL 9.8
TI-2021-17294 An issue was discovered in Concrete CMS through 8.5.5. CVSS 3.1CRITICAL 9.8

See all 197 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences