CVE-2026-18115

High

Description

Concrete CMS 9.2.0 to 9.5.2 did not enforce per-field edit_user_properties permissions on the REST API user write endpoints (PUT /ccm/api/1.0/users/{uID} and POST /ccm/api/1.0/users/{uID}/change_password). A user with an update-scoped OAuth token and permission to edit only one non-sensitive field could change another non-superuser's password, username, email, and attributes, taking over that account. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.4 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N. Thanks riodrwn for reporting.

SeverityHigh
CVSS7.4
Exploit probability—
ProductConcrete CMS
PublishedSep 15, 2026
First seenSep 15, 2026

How to fix

Affected products

ProductAffected versionsFixed in
Concrete CMS Concrete CMS9.2.0 ≤ v ≤ 9.5.2—

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