If you have selected the **Prevent vulnerable images from running** option in the project **Configuration** tab, the prevention of pulling vulnerable artifacts is determined by the scanner that is set in the project, or by the global default scanner if no scanner is configured specifically for the project. Different scanners might apply different levels of severity to artifact vulnerabilities.
{{</note>}}
1. Select the **Repositories** tab and select a repository.
For each artifact in the repository, the **Vulnerabilities** column displays the vulnerability scanning status and related information.
1. Select a artifact, or use the check box at the top to select all artifacts in the repository, and click the **Scan** button to run the vulnerability scan on this artifact.
**NOTE**: You can start a scan at any time, unless the status is **Queued** or **Scanning**. If the database has not been fully populated, you should not run a scan. The following statuses are displayed in the **Vulnerabilities** column:
* **Not Scanned:** The artifact has never been scanned.
* **Unsupported:** The artifact is not supported by the scanner.
* **Queued:** The scanning task is scheduled but has not run yet.
* **Scanning:** The scanning task is in progress and a progress bar is displayed.
* **View log:** The scanning task failed to complete. Click **View Log** link to view the related logs.
* **Complete:** The scanning task completed successfully.
If the process completes successfully, the result indicates the overall severity level, with the total number of vulnerabilities found for each severity level, and the number of fixable vulnerabilities.
* **Red:** At least one critical vulnerability found
* **Orange:** At least one high level vulnerability found
* **Yellow:** At least one medium level vulnerability found
* **Blue:** At least one low level vulnerability found
* **Green:** No vulnerabilities found
* **Grey:** Unknown vulnerabilities
1. Hover over the number of fixable vulnerabilities to see a summary of the vulnerability report.
In addition to information about the artifact, all of the vulnerabilities found in the last scan are listed. You can order or filter the list by the different columns. You can also click **Scan** in the report page to run a scan on this artifact.
## Vulnerability scanning for OCI image index
When scanning an OCI image index, Harbor will send scan requests for each of the referenced artifact which is supported by the scanner to the scanner. If the image scanning status of any referenced image is **Scanning**, the status for the OCI image index as a whole will also be **Scanning**. The scan for the index is considered successful only if all referenced images are successfully scanned. It is considered limited successful when not all referenced images are successfully scanned but at least one of referenced image is successfully scanned, otherwise it is considered failed.
When an OCI image index is successfully scanned, the summary of the vulnerability report for the OCI image index is aggregated from the individual scan results of the the artifacts referenced by the index. The vulnerability report will show both sets of statistics.
