Improper Validation of Array Index in ollama/ollama

Vulnerability

CVE-2025-1975 describes a denial-of-service vulnerability in the Ollama server version 0.5.11. The flaw stems from improper validation of array index access when processing model download requests via the /api/pull endpoint. A malicious user can customize the manifest content and spoof a service to trigger an out-of-bounds array access, causing the server to crash [2].

Exploitation

An attacker does not require authentication to exploit this vulnerability; they only need network access to the Ollama server's API. By sending a specially crafted manifest during the model pull operation, the attacker can cause the server to access an array element outside its bounds, leading to a segmentation fault or panic. The exploitation does not require any special privileges and can be performed remotely [2].

Impact

Successful exploitation results in a complete denial of service, rendering the Ollama server unavailable for legitimate users. This can disrupt any applications or services relying on the server to run AI models. No data integrity or confidentiality is affected, but availability is fully compromised.

Mitigation

As of the publication date, no patch has been announced for Ollama version 0.5.11. Users are advised to monitor the official repository for updates and apply any patches as soon as they become available [2]. Restricting network access to trusted clients can reduce exposure until a fix is deployed.