Review reviewHigh

CVE-2026-8350

Concrete CMS Concrete CMS, concrete cms

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.

CVSS: 7.5
EPSS: -
CISA KEV: Not listed
Published: 2026.05.22

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability-

Technical severityCVSS 7.5

Vulnerability overview

Affected product and versions

Product: Concrete CMS Concrete CMS, concrete cms
Affected versions: >= 5.0 <= 9.5.0, <= 9.5.0
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that Concrete CMS Concrete CMS, concrete cms and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CWE: CWE-863