CVE-2026-18120

Medium

Description

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.

SeverityMedium
CVSS5.9
Exploit probability—
ProductConcretecms Concrete Cms
PublishedSep 16, 2026
First seenSep 16, 2026

How to fix

Update
  • concretecms concrete_cms9.5.4 or later

Affected products

ProductAffected versionsFixed in
concretecms concrete_cmsv < 9.5.49.5.4

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CVE-2026-18120 · Concretecms Concrete Cms · Dark Radar