Yes. Dependency scanning can run offline when the scanner checks your lockfiles against a local copy of a vulnerability database instead of calling an online service. The trade is freshness: results are just as current as your last database import, so you need a controlled way to move updates across the gap.
How offline scanning works
A dependency scan has two inputs. One is your inventory: the packages and versions in your manifests and lockfiles. The other is vulnerability data: which versions are affected by which advisories.
Online scanners fetch the second input on every run. Offline scanners read it from disk. The documentation for one open source scanner describes it this way: offline scanning checks your project against a local database, does not download or update that database, and does not send project or dependency information anywhere. It also notes that a missing local database produces an error rather than a silent pass. That error behavior is the right design, and you should look for it in any tool you evaluate.
What you give up
- Freshness. New advisories appear daily. An offline copy that is two weeks old will miss two weeks of disclosures.
- Enrichment. Exploit signals, fix availability, and reachability data often come from live services. Ask which of those work offline.
- Convenience. Someone has to move the data.
The same documentation lists a limitation worth knowing about: commit level scanning is not supported in that offline mode. Other tools differ, so confirm what your candidate does.
A safe update routine for an isolated network
- Pick a transfer cadence. Daily is common for high risk environments, weekly for lower risk ones. Write it down.
- Download in a connected staging zone. Fetch the vulnerability data and any scanner updates there.
- Verify before you cross. Check hashes or signatures of what you downloaded, then scan the media or transfer artifact according to your own policy.
- Import and stamp. Load the data inside the isolated network and record the import date in the scan output.
- Alert on staleness. If the database age passes your limit, fail the pipeline or at least raise a ticket. Do not let a stale database produce a green result.
- Rescan stored inventories. After each import, re-evaluate existing SBOMs against the new data. A package that was clean last week may not be clean now.
What to ask a vendor or maintainer
- Does the scanner run with no network at all, including license checks and telemetry?
- How is the vulnerability data packaged, and how big is each update?
- Can the update artifact be verified offline?
- What does the report show about data age?
- Which features degrade offline?
When offline is the wrong answer
If your network can reach the internet through a controlled proxy, a proxy with an allow list is often simpler than a full air gap. You keep fresh data and still limit what can leave. Offline is for environments where even that is not permitted, such as some classified, industrial, or contractually isolated systems.
Quick check
Does an offline scan send my dependency list anywhere?
It should not. Verify this by running the scan in a network namespace with no routes and watching for failed connection attempts.
How old can the database be?
Set the limit from risk, not habit. Many teams choose one to seven days and fail builds beyond it.
Safeguard offers dependency and SBOM scanning with reachability analysis, and a free scan lets you see the output format before you plan an isolated rollout. Confirm any offline requirements with the team directly.
Sources
Last reviewed: 19 October 2026.
