Ollama Server Denial-of-Service Vulnerability via Spoofed Manifest Download

A denial-of-service vulnerability has been identified in Ollama Server version 0.5.11. This issue allows a malicious user to crash the server by customizing manifest content, spoofing a service, and downloading a model through the /api/pull endpoint. The vulnerability arises from improper validation of array index access, which can lead to a server crash.

Impact

Exploitation of this vulnerability causes the Ollama server to crash, leading to a denial-of-service condition.

Reproduction

To reproduce this vulnerability, first start the Ollama server. Then, set up a malicious server that spoofs a service by customizing the manifest content. This can be done using a simple Go application that responds with a crafted JSON manifest. Once the malicious server is running, send a POST request to the Ollama server's /api/pull endpoint, including the URL of the spoofed manifest. The Ollama server will then crash due to the unchecked array bounds access.