Vulnerability in Microsoft Windows
CVE-2026-42248
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.003 (23.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 23rd percentile — 23.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.003 · change: -0.001
Affected products
- Microsoft Windows
- Ollama — versions 0.12.10
Weakness classification (CWE)
Public proof-of-concept exploits
References
- cert.pl/en/posts/2026/04/CVE-2026-42248/ (Third Party Advisory, third-party-advisory)
- ollama.com/ (Product, product)
Frequently asked questions
- What is CVE-2026-42248?
- CVE-2026-42248 is a critical-severity vulnerability in Microsoft Windows, classified under Download of Code Without Integrity Check. CVSS score: 9.8/10. Published 2026-04-29.
- How severe is CVE-2026-42248?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2026-42248 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.