CVE-2026-8340
🔶 mediumSummary
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an attacker-chosen previously-uploaded version (downgrade to an older version of a file, or activation of a co-editor's unpublished version).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 Score
4.3
Medium
EPSS Score
0.0
Exploit Probability
Published Date
2026-05-22
First Seen: 2026-05-27
📊 Relative Risk Intelligence
This CVE is Lower Risk - more severe than 5.4% of all 328,009 vulnerabilities in our database.
#310,261
Below average severity
Severity Percentile
🎯 CISA SSVC Assessment Updated: May 22, 2026
🔍 Exploitation Status
None
No known exploits
⚙️ Automatable
NO
Requires human interaction
💥 Technical Impact
Partial
Limited system impact
🏆 Discovered By
Winston Crooker
SSVC data provided by
CISA
Last Modified
2026-05-26
Source
NVD 🔗
CVSS Vector 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
CVSS Vector 4.0
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CWE IDs (Weakness Types)