CVE-2026-8350
High
Description
Concrete CMS 9.5.0 and below is vulnerable to missing authorization in the bulk_user_assignment.php which can lead to privilege escalation to Administrative Group. Any authenticated user with access to the bulk user assignment dashboard page can add any user email to any group and can remove legitimate admins. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.5 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Vincent55 for reporting.
SeverityHigh
CVSS8.8
Exploit probability23. percentile0.3%
Product
Concretecms Concrete Cms
PublishedMay 21, 2026
First seenMay 21, 2026
Weakness typeCWE-863Incorrect authorization
How to fix
Update
- concrete5/concrete59.5.1 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| concretecms concrete_cms | v ≤ 9.5.0 | — |
| concrete5/concrete5Packagist | v < 9.5.1 | 9.5.1 |
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