Free software composition analysis tools reliably answer one question: does this dependency match a known vulnerability? They are a good start. They usually stop short of prioritising by reachability, opening fixes, enforcing policy across teams and producing audit evidence. Know those gaps before you rely on one alone.
What kinds of free option exist?
Three families, described by what they are rather than by brand.
Scanners from open source projects. OWASP Dependency-Check is an SCA tool suite. It identifies dependencies, derives a Common Platform Enumeration identifier and lists matching CVEs, drawing on the National Vulnerability Database. OSV is a vulnerability database that aggregates sources in the OpenSSF vulnerability format and can be queried by version or commit hash, with a first-party scanner built on its API.
Checks built into your code host. Many code hosting services include dependency alerts and update pull requests for supported ecosystems.
Free tiers of commercial products. These usually cap projects, scans or features. Read the limits before you depend on them.
What do free tools do well?
They match your dependency list against public data, quickly and cheaply. They run in CI. They fit a team that needs a baseline and wants no procurement. For an early project that is a real improvement over nothing.
Where do they stop?
Match quality is the first limit. Dependency-Check works by matching evidence to identifiers, so a package that is named differently across sources can produce a false match or a miss. Expect to tune and review.
Coverage is the second. Ecosystem support differs between tools. Test yours on a real repository, including a monorepo and a container image, and check that transitive dependencies are included.
Prioritisation is the third. A list sorted by severity score does not tell you which findings your code can reach or which are exploited. Without that, lists grow faster than anyone can work them.
Fixes are the fourth. Finding is cheaper than fixing. Ask whether the tool proposes a safe version or leaves you the research.
Policy and evidence come last. Organisations need rules that apply across repositories, exceptions with expiry dates, and records for auditors or customers. Free scanners rarely provide those without extra scripting.
Data freshness matters too. A scanner that relies on one database can lag behind another. Check how often it updates and what happens when it runs offline.
What should you test before choosing?
- Run two tools on the same repository and compare the findings. Note what each misses.
- Check transitive dependency coverage for your main language.
- Measure the time to a first useful result in CI.
- See whether results can feed a ticket or a pull request.
- Ask where your code or dependency list goes when the tool runs.
Safeguard also offers a free in-browser scan at gold.safeguard.sh/scan that checks up to 100 dependencies, which suits a quick look before you commit to anything.
What to do
- Start with a free scanner in CI so you have a baseline this week.
- Write down what it does not do from the list above.
- Add reachability or exploitation data to decide what to fix first.
- Define a blocking rule for the few findings you will never ship.
- Revisit the choice when you need cross-repository policy or customer evidence.
Quick check
Is a free scanner enough for a customer security review?
Often not alone. Reviews ask for inventory, process and evidence, which scanners do not produce by themselves.
Do I still need an SBOM?
Yes, if customers or regulators ask. CISA describes an SBOM as an inventory of software components, and many scanners can export one.
Sources
Last reviewed: 18 October 2026.
