Description
Concrete CMS (formerly concrete5) versions below 8.5.7 has a SSRF mitigation bypass using DNS Rebind attack giving an attacker the ability to fetch cloud IAAS (ex AWS) IAM keys.To fix this Concrete CMS no longer allows downloads from the local network and specifies the validated IP when downloading rather than relying on DNS.Discoverer: Adrian Tiron from FORTBRIDGE ( https://www.fortbridge.co.uk/ )The Concrete CMS team gave this a CVSS 3.1 score of 3.5 AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N . Please note that Cloud IAAS provider mis-configurations are not Concrete CMS vulnerabilities. A mitigation for this vulnerability is to make sure that the IMDS configurations are according to a cloud provider's best practices.This fix is also in Concrete version 9.0.0
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:NWeakness enumeration
Affected software
| Vendor | Product | Versions |
|---|---|---|
| n/a | https://github.com/concrete5/concrete5 | Affected version Concrete CMS (concrete5) 8.5.6 and below. Fixed in Concrete CMS version 8.5.7 and 9.0.0 |
References
- https://documentation.concretecms.org/developers/introduction/version-history/857-release-notesRelease Notes, Vendor Advisory
- https://hackerone.com/reports/1369312Permissions Required
- https://documentation.concretecms.org/developers/introduction/version-history/857-release-notesRelease Notes, Vendor Advisory
- https://hackerone.com/reports/1369312Permissions Required
Timeline
- Published
- Nov 19, 2021
- Last modified
- Jun 17, 2026
- NVD status
- Modified