Improper file handling in concrete5/core
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
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Composer package | concrete5/core | < 8.5.7 | 8.5.7 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H- Weakness (CWE)
CWE-330, CWE-98- Platform
- Composer
- Package
concrete5/core- Disclosed
- 23.11.2021
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-g3p2-hfqr-9m25 - CC BY 4.0
Vulnerability history: concrete5/core
All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 9
- First → latest
- 11.2021 06.2022
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 1
- High 3
- Medium 4
- Low 1
Disclosures per year
- 2021: 6
- 2022: 3
- 2023: 0
- 2024: 0
- 2025: 0
- 2026: 0
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Improper file handling in concrete5/core this entry
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