CVE-2026-8340

Concrete CMS 9.5.0 and below is vulnerable to CSRF via Backend\File::approveVersion. Victim with edit_file_contents permission is CSRF'd into publishing an attacker-chosen previously-uploaded version (downgrade to an older version of a file, or activation of a co-editor's unpublished version). The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 2.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Winston Crooker for reporting.

CVSS v3 4.3 MEDIUM

4.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.8 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes	Release Notes

Configurations

Configuration 1 (hide)

cpe:2.3:a:concretecms:concrete_cms:*:*:*:*:*:*:*:*

History

26 May 2026, 14:55

Type	Values Removed	Values Added
First Time		Concretecms concrete Cms Concretecms
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 4.3
References	~~() https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes -~~	() https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes - Release Notes
CPE		cpe:2.3:a:concretecms:concrete_cms::::::::

22 May 2026, 16:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-05-22 15:16

Updated : 2026-05-26 14:55

NVD link : CVE-2026-8340

Mitre link : CVE-2026-8340

CVE.ORG link : CVE-2026-8340

JSON object : View

Products Affected

concretecms

concrete_cms

CWE

CWE-352

Cross-Site Request Forgery (CSRF)

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