CVE-2021-22968
Improper file handling in concrete5/core
Description
A bypass of adding remote files in Concrete CMS (previously concrete5) File Manager leads to remote code execution in Concrete CMS (concrete5) versions 8.5.6 and below. The external file upload feature stages files in the public directory even if they have disallowed file extensions. They are stored in a directory with a random name, but it's possible to stall the uploads and brute force the directory name. You have to be an admin with the ability to upload files, but this bug gives you the ability to upload restricted file types and execute them depending on server configuration. To fix this, a check for allowed file extensions was added before downloading files to a tmp directory
How to fix CVE-2021-22968
To remediate CVE-2021-22968, upgrade the affected package to a fixed version below.
- —upgrade to 8.5.7 or later
Is CVE-2021-22968 being exploited?
Low — EPSS is 3.1%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 8.5.7
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.2 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H |