CVE-2026-8353

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

Assigner: ConcreteCMS
Reserved: 11.05.2026 Published: 22.05.2026 Updated: 22.05.2026

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.

Metrics

CVSS 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
CVSS Score: 2.1

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	Low	Confidentiality	None
Attack Complexity	Low	Integrity	Low	Integrity	None
Attack Requirements	Present	Availability	None	Availability	None
Privileges Required	High
User Interaction	None

CVSS 4.0

Product Status

Vendor	Concrete CMS
Product	Concrete CMS
Versions	Default: unaffected affected from 9.0 to 9.5.0 (incl.)

Vendor

Concrete CMS

Product

Concrete CMS

Versions

Default: unaffected

affected from 9.0 to 9.5.0 (incl.)

Credits

Yonatan Drori (Tenzai) finder

References

Problem Types

CWE-79 Improper neutralization of input during web page generation ('cross-site scripting') CWE

Impacts

CAPEC-592 Stored XSS