Executive brief
Ollama for Windows, a tool used to run large language models locally, fails to verify the authenticity of its software updates. Because the application performs these updates automatically and silently, an attacker could trick the software into downloading and running malicious code. This could lead to a complete takeover of the user's computer without any warning or interaction required from the user.
Technical details
Ollama for Windows contains a vulnerability where the update verification routine (CWE-494) unconditionally returns success, bypassing digital signature and trust validation. This flaw is specific to the Windows implementation and affects the silent automatic update mechanism. An attacker capable of intercepting or spoofing the update server's response can deliver a malicious executable that the application will stage and execute without user interaction. When chained with other flaws like path traversal, this can lead to persistent remote code execution. Versions 0.12.10 through 0.17.5 are confirmed vulnerable.
Affected products
- Ollama Ollama 0.12.10 through 0.17.5
Timeline
- 2026-04-29: disclosed
- 2026-04-29: advisory