CVE-2026-18120

MEDIUM CVSS 4.0: 6.3 EPSS 0.27%
Updated Sep 21, 2026
Express
Parameter Value
CVSS 6.3 (MEDIUM)
Affected Versions before 9.5.4
Fixed In 9.5.4
Type CWE-862 (Missing Authorization)
Vendor Express
Public PoC No

Concrete CMS before 9.5.3 exposed a legacy Express entry search endpoint that returned entry result JSON without invoking the canViewExpressEntries() permission check applied by the normal dashboard and CSV Export flow. An unauthenticated visitor who knew or discovered an Express entity identifier could enumerate that entity's entry search results, disclosing attribute values intended to be restricted to privileged users. For Express entities that do not support entry-specific permissions (i.e., supportsEntrySpecificPermissions() returns false), per-entry permission filtering is additionally disabled via EntryList::ignorePermissions().

The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 6.3 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks Daniel Powell for reporting.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
High
Difficult to exploit
Attack Requirements
Present
Additional conditions required
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
Low
Partial data leak
Integrity
None
No data modification
Availability
None
No disruption

CVSS Vector v4.0

Vulnerable Products 1

Configuration From (including) Up to (excluding)
Concretecms Concrete_Cms
cpe:2.3:a:concretecms:concrete_cms:*:*:*:*:*:*:*:*
— 9.5.4