CVE-2026-42248 Missing Signature Verification for Updates in Ollama
Ollama for Windows fails to verify update signatures, allowing attackers to execute malicious code via silent automatic updates.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-42248?
CVE-2026-42248 is a high-severity vulnerability in Ollama, published on 29 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Ollama for Windows does not perform integrity or authenticity verification of downloaded update executables. Unlike other platforms, the Windows implementation of the update verification routine unconditionally returns success so no digital signature or trust validation is performed before staging or executing update payloads, enabling attacker‑supplied executables to be accepted and later executed by the application.
Critically, Ollama for Windows performs silent automatic updates, so the malicious payload may be installed automatically without user awareness.
Maintainers of this project were notified early about this vulnerability, but didn't respond with the details of vulnerability or vulnerable version range. Versions from 0.12.10 to 0.17.5 were tested and confirmed as vulnerable, other versions were not tested but might also be vulnerable.
Weakness: CWE-494
Which versions are affected by CVE-2026-42248?
It affects 1 product.
Products include Ollama Ollama.
How do I fix CVE-2026-42248?
No fix published yet.
Is CVE-2026-42248 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42248 exists.
Public exploit code: 1 Metasploit module.
Other vulnerabilities in Ollama
- CVE-2025-63389 Ollama Platform has missing authentication enabling attackers to perform model management operations
- CVE-2024-45436 Ollama can extract members of a ZIP archive outside of the parent directory
- CVE-2026-7482 Ollama heap out-of-bounds read in GGUF tensor parsing leaks server process memory to unauthenticated remote attackers
- CVE-2024-37032 Ollama does not validate the format of the digest (sha256 with 64 hex digits)
- CVE-2025-15514 Ollama Multi-Modal Model Image Processing NULL Pointer Dereference
Sources
Also known as GHSA-5fjh-wjgp-25ph, MINI-3vrv-h2w3-83mv.