CVE-2026-81912

Concrete CMS before 9.5.3 is vulnerable to Cross-Site Request Forgery in the Move Multiple Groups feature

MEDIUM
5.7
CVSS Score
Published: September 11, 2026 at 07:27 PM UTC
Updated: September 24, 2026 at 08:37 PM UTC
1 product affected across 1 vendorConcrete CMS

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Severity
MEDIUM5.7
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

Description

Concrete CMS before 9.5.3 is vulnerable to Cross-Site Request Forgery in the Move Multiple Groups feature. The dashboard/users/groups/bulkupdate/confirm() endpoint moved the selected group tree nodes without validating an action token, so a state-changing group move could be processed for an authenticated user who did not initiate it. Because relocating a group under a new parent causes that group's members to inherit the parent's permissions, a forged move can change effective authorization. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 5.7 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks riodrwn for reporting.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 9.5.45.0.0 ≤ v ≤ 9.5.25.0.0
Affected range stops below 9.5.4, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.7MEDIUMConcreteCMS
Vector?

Quick Info

StatusANALYZED
CWE
CWE-352

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