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Description

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.

PUBLISHED Reserved 2026-05-09 | Published 2026-05-21 | Updated 2026-05-22 | Assigner ConcreteCMS




HIGH: 7.3CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Problem types

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

Product status

Default status
unaffected

5 (git)
affected

Credits

Alfin Joseph finder

References

documentation.concretecms.org/...n-history/951-release-notes release-notes

cve.org (CVE-2026-8203)

nvd.nist.gov (CVE-2026-8203)

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