CVE-2021-22966: Concretecms Concrete CMS

High severity, CVSS 8.8. EPSS: 1% chance of exploitation in the next 30 days.

Privilege escalation from Editor to Admin using Groups in Concrete CMS versions 8.5.6 and below. If a group is granted "view" permissions on the bulkupdate page, then users in that group can escalate to being an administrator with a specially crafted curl. Fixed by adding a check for group permissions before allowing a group to be moved. Concrete CMS Security team CVSS scoring: 7.1 AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:HCredit for discovery: "Adrian Tiron from FORTBRIDGE ( https://www.fortbridge.co.uk/ )"This fix is also in Concrete version 9.0.0

Affected products

• Concretecms Concrete CMS: before 8.5.7 (fixed in 8.5.7)

Published 2021-11-19. Last modified 2026-06-17.