CVE-2020-8866
CWE-434Published: March 23, 2020· Updated: Jun 17, 2026
Official Description
This vulnerability allows remote attackers to create arbitrary files on affected installations of Horde Groupware Webmail Edition 5.2.22. Authentication is required to exploit this vulnerability. The specific flaw exists within add.php. The issue results from the lack of proper validation of user-supplied data, which can allow the upload of arbitrary files. An attacker can leverage this in conjunction with other vulnerabilities to execute code in the context of the www-data user. Was ZDI-CAN-10125.
Technical Analysis
CVE-2020-8866 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
A successful exploit results in full integrity compromise (data manipulation), with a CVSS base score of 6.5.
A proof-of-concept (PoC) exploit exists for CVE-2020-8866. While not yet confirmed in active campaigns, the availability of PoC code increases exploitation risk substantially.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
Official Patches & Advisories
All References (6)
Quick Facts
Related CVEs (CWE-434)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2020-8866 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts