Plex media server 1.21 and before is vulnerable to ddos reflection attack via plex service.

An issue was discovered in Plex Media Server through 1.24.4.5081-e362dc1ee. An attacker (with a foothold in a endpoint via a low-privileged user account) can access the exposed RPC service of the update service component. This RPC functionality allows the attacker to interact with the RPC functionality and execute code from a path of his choice (local, or remote via SMB) because of a TOCTOU race condition. This code execution is in the context of the Plex update service (which runs as SYSTEM).

Plex Media Server before 0.9.9.3 allows remote attackers to bypass the web server whitelist, conduct SSRF attacks, and execute arbitrary administrative actions via multiple crafted X-Plex-Url headers to system/proxy, which are inconsistently processed by the request handler in the backend web server.

Multiple directory traversal vulnerabilities in Plex Media Server before 0.9.9.3 allow remote attackers to read arbitrary files via a .. (dot dot) in the URI to (1) manage/ or (2) web/ or remote authenticated users to read arbitrary files via a .. (dot dot) in the URI to resources/.

Tautulli versions 2.1.38 and below allows remote attackers to bypass intended access control in Plex Media Server because the X-Plex-Token is mishandled and can be retrieved from Tautulli. NOTE: Initially, this id was associated with Plex Media Server 1.18.2.2029-36236cc4c as the affected product and version. Further research indicated that Tautulli is the correct affected product.

In Plex Media Server 1.13.2.5154, the XML parsing engine for SSDP/UPnP functionality is vulnerable to an XML External Entity Processing (XXE) attack. Remote, unauthenticated attackers can use this vulnerability to: (1) Access arbitrary files from the filesystem with the same permission as the user account running Plex, (2) Initiate SMB connections to capture a NetNTLM challenge/response and crack to cleartext password, or (3) Initiate SMB connections to relay a NetNTLM challenge/response and achieve Remote Command Execution in Windows domains.

The Camera Upload functionality in Plex Media Server through 1.18.2.2029 allows remote authenticated users to write files anywhere the user account running the Plex Media Server has permissions. This allows remote code execution via a variety of methods, such as (on a default Ubuntu installation) creating a .ssh folder in the plex user's home directory via directory traversal, uploading an SSH authorizedkeys file there, and logging into the host as the Plex user via SSH.