CVE-2026-42248
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedOllama 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceOllama for Windows fails to perform integrity or authenticity verification of downloaded update executables. The Windows-specific update verification routine unconditionally returns success, bypassing digital signature and trust validation entirely. This allows malicious update payloads to be staged and executed by the application.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data>= 0.12.10, <= 0.17.5CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Verify Ollama is installed on WindowsCheck for Ollama installation in Program Files, Program Files (x86), or run 'where ollama' in Command Prompt/PowerShell to locate the executableAffected if Ollama executable is found on the system
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Determine installed Ollama versionRun 'ollama --version' in Command Prompt or PowerShell, or right-click the ollama.exe file in File Explorer and view Properties > Details to see the File VersionAffected if Installed version is >= 0.12.10 and <= 0.17.5
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Check if automatic updates are enabledInspect Ollama's configuration file (typically located in %APPDATA%\ollama\config.json or %LOCALAPPDATA%\ollama\config.json) for update-related settings such as 'auto_update', 'check_updates', or similar flagsAffected if Automatic update checking is enabled and version is within affected range
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Inspect Ollama update configuration directoryExamine the contents of the Ollama data directory (%APPDATA%\ollama\ or %LOCALAPPDATA%\ollama\) for any downloaded update files, temporary update payloads, or unexpected .exe files staged in these foldersAffected if Unexpected update executables or staging files are present in Ollama directories
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Review network connections to update endpointsUse 'netstat -ano | findstr ollama' or Windows Firewall event logs to inspect outbound connections from Ollama processes to verify if update check requests are being made to expected official endpointsAffected if Ollama is making update requests and version falls within affected range
A user is affected if Ollama for Windows is installed with version 0.12.10 through 0.17.5 and automatic update functionality is enabled, allowing unsigned update payloads to execute without validation.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataDisable automatic updates until a patch is available; manually verify and source update executables from official channels only. Consider network-level controls to restrict update server communication.
- Consultation6.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-42248 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-42248 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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