High severity · published Sep 15, 2026
CVE-2026-18115
In Concrete CMS 9.2.0 to 9.5.2, Missing Authorization in REST API Users update() and change_password Enables Account Takeover.
7.4
CVSS
0.4%
EPSS
No
On KEV
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.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CC
Concrete CMS · Concrete CMS
9.2.0 through 9.5.2 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-18115
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-18115
documentation.concretecms.org
https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes
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