Impact

This vulnerability affects all Emby Server versions - beta and stable up to the specified versions. It allows an attacker to gain full administrative access to an Emby Server (for Emby Server administration, not at the OS level,). Other than network access, no specific preconditions need to be fulfilled for a server to be vulnerable.

Patches

Quick Fix

A quick fix will be rolled out via an update to one of the default-included Emby Server plugins. This way is chosen because many users are updating their servers manually while plugin updates are typically configured to be applied automatically. This allows to get a patch deployed to a large amount of servers within a single day.

Server Patches

Patched versions for both, Emby Server stable and Emby Server beta are available now.

All Emby Server owners are strongly encouraged to apply those updates as soon as possible.

Workarounds

[!NOTE] These workarounds are OBSOLETE now. Please update Emby Server instead!

As and immediate remedy, it is possible to set restricted file system permissions on the passwordreset.txt file in the configuration folder of Emby Server. If it doesn't exist, users can create the file themselves or just call the ForgotPassword API once, which will create the file.

On Windows, users can set DENY permissions for "Authenticated users" and on Linux, permissions can be set via sudo chmod 444 passwordreset.txt. This will make the API request fail, which completely eliminates the vulnerability.

Emby Server before 4.5.0 allows SSRF via the Items/RemoteSearch/Image ImageURL parameter.

Emby Server < 4.7.12.0 is vulnerable to a login bypass attack by setting the X-Forwarded-For header to a local IP-address.

Emby Server is a user-installable home media server which stores and organizes a user's media files of virtually any format and makes them available for viewing at home and abroad on a broad range of client devices. This vulnerability may allow administrative access to an Emby Server system, depending on certain user account settings. By spoofing certain headers which are intended for interoperation with reverse proxy servers, it may be possible to affect the local/non-local network determination to allow logging in without password or to view a list of user accounts which may have no password configured. Impacted are all Emby Server system which are publicly accessible and where the administrator hasn't tightened the account login configuration for administrative users. This issue has been patched in Emby Server Beta version 4.8.31 and Emby Server version 4.7.12.

Emby Server is a personal media server. Prior to version 4.8.1.0 and prior to Beta version 4.9.0.0-beta, a malicious user can send an authentication request with a manipulated X-Emby-Client value, which gets added to the devices section of the admin dashboard without sanitization. This issue has been patched in version 4.8.1.0 and Beta version 4.9.0.0-beta.

Emby Server allows unauthenticated file read.

Stored Cross Site Scripting vulnerability in Emby Media Server Emby Media Server 4.8.3.0 allows a remote attacker to escalate privileges via the notifications.html component.

A vulnerability was found in Media Browser Emby Server 4.7.13.0 and classified as problematic. This issue affects some unknown processing of the file /web/. The manipulation leads to cross site scripting. The attack may be initiated remotely. The exploit has been disclosed to the public and may be used. It is recommended to upgrade the affected component. The associated identifier of this vulnerability is VDB-236183.

In Emby Server 4.6.7.0, the playlist name field is vulnerable to XSS stored where it is possible to steal the administrator access token and flip or steal the media server administrator account.

Emby Server versions < 4.6.0.50 is vulnerable to Cross Site Scripting (XSS) vulnerability via a crafted GET request to /web.

Emby Server allows unauthenticated file read.