CVE-2026-8340

Concrete CMS 9.5.0 and below is vulnerable to CSRF via Backend\File::approveVersion

State: Published
Severity: 2.3 Low
Published: May 22, 2026
Updated: May 22, 2026
Reserved: May 11, 2026

Description

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an attacker-chosen previously-uploaded version (downgrade to an older version of a file, or activation of a co-editor's unpublished version).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.

Scores

CVSS	Score	Vector	Source
4.0	2.3 Low	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	ConcreteCMS

Weaknesses

CWE-352 Cross-Site request forgery (CSRF)

Affected Products

Product	Versions
Concrete CMSConcrete CMS	5.0 through 9.5.0Affected

References

https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notesrelease-notes

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