TI-2026-07224 Aliases CVE-2026-8203 GHSA-9v2g-37mp-qpxf

Cross-site scripting in Concrete CMS

LOW 33CWE-79Published 2026-05-21 · Updated 2026-05-22

Key facts

Attack vector: Network
Privileges required: High
User interaction: Passive
Attack complexity: High
Attack requirements: Present
Impact type: Cross-site scripting
Confidentiality · integrity · availability: High · High · High
Fix status: Fixed

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

Summary

Concrete CMS 9.5.0 and below has Stored XSS on the height parameter. The controller does not validate or sanitize $height. Any user with editor privileges can inject malicious JavaScript that executes in the context of any visitor's browser, potentially leading to session hijacking, credential theft, or other malicious actions. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.3 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Alfin Joseph for reporting.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00122 1st 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: Total

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)	before 9.5.1	9.5.1	Patch available	GHSA-9v2g-37mp-qpxf

concrete5/concrete5 (Packagist) Vendor— Affected before 9.5.1 Fixed in 9.5.1 Patch available GHSA-9v2g-37mp-qpxf

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:concretecms:concrete_cms::::::::	up to 9.5.0	Vulnerable	Concrete CMS

cpe:2.3:a:concretecms:concrete_cms:*:*:*:*:*:*:*:* Versions up to 9.5.0 Vulnerable ·Concrete CMS

Remediation

Fix · GHSA-9v2g-37mp-qpxf concrete5/concrete5 (Packagist) Fixed in 9.5.1 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-8203
2026-10-03 Alias added: GHSA-9v2g-37mp-qpxf

References

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-8203

Other 2

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