CVE-2026-5530 in Ollama
Summary
by MITRE • 04/05/2026
A flaw has been found in Ollama up to 0.18.1. This issue affects some unknown processing of the file server/download.go of the component Model Pull API. Executing a manipulation can lead to server-side request forgery. The attack can be launched remotely. The vendor was contacted early about this disclosure but did not respond in any way.
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Analysis
by VulDB Data Team • 07/24/2026
The vulnerability identified in Ollama version 18.1 represents a critical server-side request forgery flaw that emerges from improper handling of file server/download.go within the Model Pull API component. This issue stems from insufficient validation and sanitization of user-supplied input during the file download process, creating an avenue for malicious actors to manipulate the system's request handling mechanisms. The flaw exists in the core infrastructure that manages model retrieval operations, making it particularly dangerous as it directly impacts the software's ability to fetch and process external resources.
The technical exploitation of this vulnerability occurs through manipulation of the Model Pull API's file download functionality where attacker-controlled input can be injected into the server-side request processing chain. When a user initiates a model pull operation, the system processes the request in the download.go file which fails to properly validate or sanitize the target URL or resource identifier. This allows an attacker to construct malicious requests that bypass normal security controls and potentially access internal systems or resources that should remain isolated from external access. The flaw operates at the application layer where the software processes user input without adequate boundary checking, creating a direct path for unauthorized data access or system compromise.
The remote exploitation capability of this vulnerability presents significant operational risks to organizations deploying Ollama in production environments. Attackers can leverage this flaw to perform unauthorized access to internal network resources, potentially leading to data exfiltration, lateral movement within the network, or even complete system compromise. The impact extends beyond simple information disclosure as the vulnerability could enable attackers to manipulate the software's behavior, potentially causing denial of service conditions or redirecting requests to malicious endpoints. Organizations using Ollama for machine learning model management face particular risk since this flaw could allow unauthorized access to sensitive AI models or training data.
Security professionals should prioritize immediate mitigation efforts including implementing network segmentation to limit access to Ollama services, deploying web application firewalls to monitor and filter suspicious requests, and applying any available vendor patches or workarounds. The vulnerability aligns with CWE-918 Server-Side Request Forgery which specifically addresses weaknesses in applications that fail to properly validate and sanitize external resource identifiers. From an ATT&CK framework perspective, this flaw maps to T1190 Exploit Public-Facing Application and potentially T1071.004 Application Layer Protocol Web Protocols, as it enables attackers to manipulate web-based API endpoints for unauthorized access. Organizations should also implement monitoring solutions that can detect anomalous request patterns or attempts to access unexpected network resources during model pull operations.
The lack of vendor response to early disclosure efforts compounds the risk, leaving organizations without official patches or mitigation guidance. This scenario exemplifies the importance of maintaining awareness of third-party software vulnerabilities and implementing proactive security measures even when vendors fail to respond promptly to security concerns. Security teams should consider implementing temporary workarounds such as disabling external model pull functionality or restricting access to the affected API endpoints until proper patches are available. The vulnerability underscores the critical need for comprehensive input validation and proper resource handling in all components that process user-supplied data, particularly those involved in network communication and file operations.