CVE-2020-8866

MEDIUM

Horde Groupware Webmail Edition 5.2.22 - RCE

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 2 public exploits for CVE-2020-8866. PoCs published by Andrea Cardaci.

AI-analyzed exploit summary This exploit targets a file inclusion vulnerability in Horde Webmail, allowing an authenticated attacker to upload a malicious .inc file and include it via a path traversal in the 'trean_Block_Bookmarks' block, leading to remote code execution.

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.

Exploits (2)

exploitdb WORKING POC
by Andrea Cardaci · pythonwebappsphp
https://www.exploit-db.com/exploits/48209

This exploit targets a file inclusion vulnerability in Horde Webmail, allowing an authenticated attacker to upload a malicious .inc file and include it via a path traversal in the 'trean_Block_Bookmarks' block, leading to remote code execution.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: Horde Webmail (version not specified, but CVE-2020-8866 affects versions before 5.2.22)
Auth required
Prerequisites: Valid credentials for the Horde Webmail instance · Access to the target's /tmp directory for file upload
devstral-2 · analyzed Feb 16, 2026 Full analysis →
exploitdb WORKING POC
by Andrea Cardaci · pythonwebappsphp
https://www.exploit-db.com/exploits/48210

This exploit leverages PHAR deserialization in Horde Webmail to achieve remote code execution by uploading a malicious PHAR file, triggering its deserialization via a syndicated feed block, and executing arbitrary PHP code.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: Horde Webmail (versions affected by CVE-2020-8866)
Auth required
Prerequisites: Valid credentials for Horde Webmail · Ability to upload files to the temporary directory · PHP execution environment
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (3)

Core 3
Core References
Third Party Advisory, VDB Entry x_refsource_misc
https://www.zerodayinitiative.com/advisories/ZDI-20-275/
Mailing List, Vendor Advisory x_refsource_misc
https://lists.horde.org/archives/announce/2020/001288.html
Mailing List, Third Party Advisory mailing-list x_refsource_mlist
https://lists.debian.org/debian-lts-announce/2020/03/msg00036.html

Scores

CVSS v3 6.5
EPSS 0.0958
EPSS Percentile 94.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Details

CWE
CWE-434
Status published
Products (3)
debian/debian_linux 8.0
horde/groupware 5.2.22
horde/horde_form < 2.0.20
Published Mar 23, 2020
Tracked Since Feb 18, 2026