CVE-2026-42248
CVE-2026-42248 is a critical-severity vulnerability in Ollama with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-494.
Key facts
- Severity: Critical (CVSS 3.x base score 9.8)
- CVSS v4: 7.7
- EPSS exploit prediction: 0% (30th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-26210
- Weakness: CWE-494
- Affected product: Ollama
- Published:
- Last modified:
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.
Frequently asked questions
- What is 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.
- How severe is CVE-2026-42248?
- CVE-2026-42248 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2026-42248 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-42248?
- CVE-2026-42248 affects Ollama. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-42248?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
- Does CVE-2026-42248 have an EU (EUVD) identifier?
- Yes. CVE-2026-42248 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26210.
- When was CVE-2026-42248 published?
- CVE-2026-42248 was published on 2026-04-29 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:a:ollama:ollama:*:*:*:*:*:*:*:*
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Threat intelligence
Threat-intel indicators referencing this CVE:
- 46.224.203.89 (ipv4-addr)