Snyk CLI for open-source C++ scans

Snyk CLI for open-source C/C++

To explore the vulnerabilities for C/C++, search the Snyk Vuln DB. Snyk tests your code against this database, which is periodically updated with the latest source code from online sources. For details, see Snyk Vulnerability Database.

For Snyk to scan the open-source Project, the dependencies must be available as source code in the scanned directory. If the dependencies are in a different location, that location must be scanned. For details, see Source code dependencies must be in the scanned folder.

When you run the snyk test --unmanaged command, Snyk does the following:

  1. Converts all files from your current folder into a list of hashes.

  2. Sends hashes to the Snyk scan server to compute the dependencies list.

  3. Queries the database to find a list of potentially matching dependencies.

  4. Links the dependencies to the known vulnerabilities.

  5. Displays the results.

Scanning archives

By default, archives are not scanned. However, the CLI can recursively extract archives to analyze the source code inside.

To enable archive extraction, specify the depth of the extraction using the --max-depth option.

The supported archive formats are:

  • zip-like archives

  • tar archives

  • tar with gzip compression algorithm

Source code dependencies must be in the scanned folder

For the CLI to be able to find dependencies in your source code, enough of the full dependencies source code must be present in the scanned folder.

Having a large percentage of files in their original (unchanged) form is critical to accurately identifying dependencies and reporting the correct set of vulnerabilities back. Modifying that source code reduces the confidence of the scanning engine, resulting in less accurate results. Other potential issues could include dependencies not being identified or being identified incorrectly, as a different version or even a different package.

The example that follows shows a typical package with dependencies listed:

├── deps
│   ├── curl-7.58.0
│   │   ├── include
│   │   │   ├──
│   │   │   ├──
│   │   │   ├── README
│   │   │   └── curl
│   │   ├── install-sh
│   │   ├── lib
│   │   │   ├── asyn.h
│   │   │   ├── base64.c
│   │   │   ├──
│   │   │   ├── config-amigaos.h
│   │   │   ├── conncache.c
│   │   │   ├── conncache.h
│   │   ├── src
│   │   │   ├── tool_binmode.c
│   │   │   ├── tool_binmode.h
│   │   │   ├── tool_bname.c
│   │   │   ├── tool_xattr.c

Support for releases

Only official releases are tracked. Commits, including into the default branch, are not identified unless included in an official release or tag.

Data collection during a scan

When you scan C++ Projects, the following data is collected and may be stored for troubleshooting purposes:

Hashes of the scanned files: All files are converted to a list of irreversible hashes.

Relative paths to scanned files: The paths to files relative to the directory being scanned are included for better identification and matching. Example: ./project-name/vendor/bzip2-1.0.6/blocksort.c

Displaying dependencies

To display dependencies, use the --print-deps option:

$ snyk test --unmanaged --print-deps

Testing /Users/user/src/foo...

  purl: pkg:generic/curl@7.29.0?
  confidence: 1.000|nih-at/libzip@1.8.0
  purl: pkg:generic/libzip@1.8.0?
  confidence: 1.000|madler/zlib@1.2.11
  purl: pkg:generic/zlib@1.2.11?
  confidence: 1.000

To learn what files contributed to each dependency being identified, use the --print-dep-paths option:

$ snyk test --unmanaged --print-dep-paths

Testing /Users/user/src/foo...

  purl: pkg:generic/curl@7.29.0?
  confidence: 1.000
  matching files:
    - curl-7.29.0/
    - curl-7.29.0/CHANGES
    - curl-7.29.0/CMake/
    ... and 1766 more files|nih-at/libzip@1.8.0
  purl: pkg:generic/libzip@1.8.0?
  confidence: 1.000
  matching files:
    - libzip-1.8.0/
    - libzip-1.8.0/AUTHORS
    - libzip-1.8.0/CMakeLists.txt
    ... and 780 more files|madler/zlib@1.2.11
  purl: pkg:generic/zlib@1.2.11?
  confidence: 1.000
  matching files:
    - zlib-1.2.11/CMakeLists.txt
    - zlib-1.2.11/ChangeLog
    - zlib-1.2.11/FAQ
    ... and 249 more files

This output also shows how confident Snyk is about the identified dependency and its version. To sww how confident Snyk is about the identified dependency and its version, you can, use the --print-deps or --print-dep-paths option.

Understanding the confidence level

The confidence level shows how confident Snyk is about the actual identification of the dependency. The number can be between 0 and 1 and the higher the number is, the more accurate the identification. A confidence level of 1 means that all the files in the source tree fully matched all the expected files in the Snyk database.

curl| confidence: 0.993

You may need to change the source code of the dependencies that you use in your software. As Snyk uses file signatures to find the closest possible match to an open-source library, your changes may decrease the accuracy of the identification of the actual library.

JSON output

To get machine-readable output in JSON, use the --json option:

$ snyk test --unmanaged --json
    "issues": [
        "pkgName": "curl|",
        "pkgVersion": "7.58.0",
        "issueId": "CVE-2019-5481",
        "fixInfo": {
          "isPatchable": false,
          "isPinnable": false
    "issuesData": {
      "CVE-2019-5481": {
        "severity": "high",
        "CVSSv3": "",
        "originalSeverity": "high",
        "severityWithCritical": "high",
        "type": "vuln",
        "alternativeIds": [
        "creationTime": "2019-09-16T19:15:00.000Z",
        "disclosureTime": "2019-09-16T19:15:00.000Z",
        "modificationTime": "2020-10-20T22:15:00.000Z",
        "publicationTime": "2019-09-16T19:15:00.000Z",
        "credit": [
        "id": "CVE-2019-5481",
        "packageManager": "cpp",
        "packageName": "curl|",
        "language": "cpp",
        "fixedIn": [
        "patches": [],
        "exploit": "No Data",