CVE-2021-40109 json
A SSRF issue was discovered in Concrete CMS through 8.5.5.
published 2021-09-27 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-27298
- cvss
- 6.4
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 45%
- public exploits
- 0
- none known
Summary
A SSRF issue was discovered in Concrete CMS through 8.5.5. Users can access forbidden files on their local network. A user with permissions to upload files from external sites can upload a URL that redirects to an internal resource of any file type. The redirect is followed and loads the contents of the file from the redirected-to server. Files of disallowed types can be uploaded.
Patch / fix
- concretecms concrete_cms 8.5.6
Exploit prediction
0.54% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 6.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N |
| NVD | 2.0 | 5.5 | AV:N/AC:L/Au:S/C:P/I:P/A:N |
Classification
- Weakness
-
- CWE-918 Server-Side Request Forgery
References
-
documentation.concretecms.org
/developers/introduction/version-history/856-release-notes
release-notes, vendor-advisory
-
hackerone.com
/reports/1102105
permissions-required
Sources
- CVE List CVE-2021-40109
- NVD CVE-2021-40109
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.