Arbitrary file upload in Concretecms Concrete Cms
CVE-2021-22968
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.Concrete CMS Security Team gave this a CVSS v3.1 score of 5.4 AV:N/AC:H/PR:H/UI:R/S:C/C:N/I:H/A:NThis fix is also in Concrete version 9.0.0
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.032 (87.8th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 88th percentile — 87.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.031 · newest: 0.032 · change: +0.001
Affected products
- Concretecms Concrete Cms
- Https://github.com/concrete5/concrete5 — versions Concrete CMS version 9.0 and version 8.5.7
Weakness classification (CWE)
Public proof-of-concept exploits
References
- documentation.concretecms.org/developers/introduction/version-history/857-relea… (Release Notes, Vendor Advisory)
- hackerone.com/reports/1350444 (Exploit, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-22968?
- CVE-2021-22968 is a high-severity vulnerability in Concretecms Concrete Cms, classified under PHP Remote File Inclusion. CVSS score: 7.2/10. Published 2021-11-19.
- How severe is CVE-2021-22968?
- High severity. CVSS v3 base score is 7.2 out of 10.
- Is CVE-2021-22968 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.