Packagist · egroupware/egroupware
EGroupware has a Remote Code Execution Vulnerability
A critical vulnerability has been identified in EGroupware that may lead to Remote Code Execution (RCE). The issue allows an authenticated attacker to execute arbitrary commands on the server. If user self-registration is enabled, the vulnerability may be exploitable without prior authentication.
The vulnerability stems from improper authorization checks combined with a file write primitive and an arbitrary file read vulnerability, which together enable full system compromise.
The vulnerability originates in:
EGroupware\SmallParT\Widgets\SmallPartMediaRecorder::ajax_upload()
The function attempts to verify whether the current user is a teacher of the specified course ID before allowing a file upload.
The critical authorization check ensures that the course access control list (ACL) contains:
$required_acl (self::ROLE_TEACHER, i.e., 3)
However, the course_acl value is derived from user-controlled request data.
Bypass Technique
A crafted request can manipulate the participant_role value inside the request body:
{
"video": {
"course_id": {
"participants": [
{
"account_id": "7",
"name": "Test",
"joined_at": "2026-01-10",
"participant_role": 3
}
],
"account_id": "7",
"course_id": "1"
},
"video_hash": ".",
"video_type": "file_here"
}
}
Because the course ACL is taken from participant_role, setting it to 3 allows bypassing the isTeacher check.
After bypassing authorization, the function uploads the provided file into a controllable file path.
The file path is derived from the video_type (or video_path) value, enabling path traversal.
Due to file permission restrictions (server running as www-data), writable targets are limited. One viable target is ./header.inc.php
Writing a simple PHP webshell may not immediately execute due to OPcache.
An invalid header.inc.php file will break the system and prevent the server from running.
Therefore, a valid file structure must be preserved.
A second vulnerability allows arbitrary file read via:
/egroupware/index.php?menuaction=importexport.importexport_export_ui.download&_filename=../../../usr/share/egroupware/header.inc.php&_suffix=txt&_type=text/plain&filename=leak
The issue resides in:
importexport_export_ui::download
The _filename parameter is user-controlled and used to read arbitrary files.
This allows retrieving the original header.inc.php content.
By combining: Arbitrary file read (to retrieve valid header.inc.php); Arbitrary file write (to overwrite it with modified content), an attacker can inject controlled PHP code while preserving file validity.
This results in Remote Code Execution after server restart, or OPcache expiration. An alternative impact includes modifying the admin setup password to gain full system control.
Remote Code Execution Full system compromise Arbitrary file read Arbitrary file write Potential complete takeover of EGroupware instance
This finding was discovered by Huong Kieu of Cenobe Security (https://cenobe.com/)
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Check my repoSources: CISA KEV (public domain), OSV.dev & GitHub Advisory Database (CC-BY-4.0), FIRST EPSS, NVD/CWE (public domain). Served live from the Stateward advisory database.