CVE-2021-22968
mediumpriority · track · 30OT risk · elevatedEPSS 0.032 · 88 %ileEUUSEPSS · scored 2026-10-28
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
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.5–7.2
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (3)
Products and version ranges known to be affected.
advisories (1)
Vendor and ecosystem advisories describing this.
- GHSA-g3p2-hfqr-9m25Improper file handling in concrete5/core2021-11-23ghsa · osvUS
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
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (7)
External citations — patches, advisories, analysis.
- https://documentation.concretecms.org/developers/introduction/version-history/857-release-notescnnvd
- https://hackerone.com/reports/1350444cnnvd
- https://nvd.nist.gov/vuln/detail/CVE-2021-22968cnnvd
- https://documentation.concretecms.org/developers/introduction/version-history/857-release-notesenisa_euvd
- https://hackerone.com/reports/1350444enisa_euvd
- https://documentation.concretecms.org/developers/introduction/version-history/857-release-notesRelease NotesVendor Advisorynvd
- https://hackerone.com/reports/1350444ExploitThird Party Advisorynvd
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