A flaw was found in multipathd. A local attacker with access to the multipathd UNIX control socket can exploit this vulnerability by sending valid commands and then ceasing to read replies. This action can cause the multipathd listener thread to block, leading to a Denial of Service (DoS) where legitimate Inter-Process Communication (IPC) operations may hang or time out. This issue does not result in privilege escalation, arbitrary code execution, or impact data confidentiality or integrity.
Weakness
The product uses a non-blocking model that relies on a single threaded process for features such as scalability, but it contains code that can block when it is invoked.
Extended Description
When an attacker can directly invoke the blocking code, or the blocking code can be affected by environmental conditions that can be influenced by an attacker, then this can lead to a denial of service by causing unexpected hang or freeze of the code. Examples of blocking code might be an expensive computation or calling blocking library calls, such as those that perform exclusive file operations or require a successful network operation. Due to limitations in multi-thread models, single-threaded models are used to overcome the resource constraints that are caused by using many threads. In such a model, all code should generally be non-blocking. If blocking code is called, then the event loop will effectively be stopped, which can be undesirable or dangerous. Such models are used in Python asyncio, Vert.x, and Node.js, or other custom event loop code.