Executive brief
Redaxo CMS, a content management system used for building and managing websites, contains a security flaw in its Mediapool component. An authorized user with basic editor permissions can bypass security filters to upload malicious files to the server. This could allow an attacker to take full control of the website, access sensitive data, or disrupt operations.
Technical details
An arbitrary file upload vulnerability exists in the Mediapool Addon (versions prior to 2.4.0) within Redaxo CMS (versions 5.5.1 and older). The vulnerability stems from an incomplete blacklist filter that blocks common PHP extensions but fails to account for version-specific extensions such as .php71 or .php53. An authenticated attacker with 'editor' privileges can upload a malicious script using these obfuscated extensions to bypass the filter. Once uploaded, the attacker can execute arbitrary code on the server, leading to full system compromise. The issue was addressed in Mediapool 2.4.0 and Redaxo CMS 5.6.0.
Affected products
- Redaxo Mediapool Addon <= 5.5.1
- Redaxo Redaxo CMS <= 5.5.1
Timeline
- 2018-03-08: disclosed: Vulnerability reported to vendor
- 2018-06-08: patched: Fixed in Mediapool 2.4.0 and Redaxo CMS 5.6.0
- 2018-06-13: other: Exploit-DB PoC published
- 2026-05-23: advisory: NVD/VulnCheck advisory published