In November 2020, npm's request library — a dependency pulled in roughly 18 million times a week — was formally deprecated by its maintainer after years of declining activity, leaving every downstream project depending on a package that would never receive another security patch. Two years earlier, event-stream became a cautionary tale of a different kind: a maintainer handed the project off to an unfamiliar contributor who quietly inserted a cryptocurrency-stealing payload into a nested dependency. Neither case started with a CVE. Both started with a package quietly losing the attention that once kept it safe. Deprecated and unmaintained open source packages don't announce themselves — they decay silently until a vulnerability lands with no one left to fix it. Snyk, one of the most widely deployed software composition analysis (SCA) tools, builds package-health detection directly into its scanning pipeline so teams can see that decay coming. Here is how that detection mechanism actually works, based on Snyk's publicly documented approach.
What does Snyk consider a "deprecated" or "unmaintained" package?
Snyk treats deprecation and unmaintenance as two related but distinct signals. A package is marked deprecated when its own registry metadata says so — for example, when a publisher runs npm deprecate on an npm package, or when a PyPI or RubyGems maintainer archives a project and updates its listing. Snyk ingests that registry-level metadata and surfaces the deprecation notice directly inside snyk test results and pull request checks, so a developer adding request to a package.json today sees the maintainer's own warning at scan time rather than discovering it later.
Unmaintained is a broader, inferred category that doesn't require the maintainer to say anything at all. A project can go quiet — no commits, no releases, no responses to issues — for a year or more without ever being formally deprecated. That's the gap Snyk Advisor's scoring model is built to close, because a silently abandoned package is arguably a bigger blind spot than one that's openly deprecated: nobody gets a notification when the second scenario happens.
How does Snyk Advisor score a package's maintenance health?
Snyk Advisor assigns every tracked package a health score, visible publicly at snyk.io/advisor, built from four weighted pillars: popularity, maintenance, community, and security. Each pillar rolls up several underlying signals rather than a single number, which is what lets Advisor distinguish "quiet because it's stable" from "quiet because it's abandoned."
The maintenance pillar specifically looks at things like time elapsed since the last published release, commit frequency over the trailing period, how quickly open issues and pull requests get triaged, and whether release cadence has dropped off relative to the project's own history. A package with a low maintenance score isn't necessarily insecure yet — but Snyk's premise is that low maintenance activity is a leading indicator of future risk, since an unmaintained package can't respond when the next vulnerability disclosure hits it. Advisor covers ecosystems including npm, PyPI, Maven, Go, and RubyGems, and updates scores on an ongoing basis rather than as a one-time snapshot.
Where does Snyk pull its decay signals from?
Snyk aggregates data from two layers: the package registry itself, and the linked source repository. From registries like npm, PyPI, Maven Central, RubyGems, and the Go module proxy, Snyk pulls publish dates, download counts, and any explicit deprecation flags the publisher has set. From the linked repository — most commonly GitHub — it pulls commit history, issue and pull request activity, contributor counts, and star growth over time.
That registry-plus-repository combination matters because either source alone can mislead. A package can keep receiving downloads long after its source repository has gone silent, and a repository can look active from stray commits (README edits, CI config tweaks) without any of that activity touching the actual published code. Snyk also layers in its own vulnerability intelligence, curated by its in-house security research team, which manually reviews and annotates advisories — including flags for packages found to be malicious, typosquatted, or effectively end-of-life. This manual curation step is what lets Snyk catch cases like event-stream, where the automated activity signals (a new maintainer committing code) would have looked superficially healthy.
How does Snyk surface a stale dependency during development and in CI/CD?
Snyk surfaces package health at three points in the workflow: the IDE plugin, CLI scans, and pull request checks. Running snyk test locally or in a CI pipeline returns the same health-score data Advisor shows publicly, attached directly to the flagged dependency in the scan output, alongside a suggested upgrade path or alternative package where one exists. The GitHub, GitLab, and Bitbucket integrations bring that same check into the pull request itself, so a reviewer sees a deprecation or low-maintenance warning on the diff before merging a new dependency in, rather than finding out weeks later.
Snyk also supports snyk monitor, which takes a persistent snapshot of a project's dependency tree at commit or deploy time rather than only scanning at the moment a developer runs a command. That snapshot is what enables detection after the fact — a capability that matters because package health is not static.
What happens when a package you already depend on goes stale after you've adopted it?
This is where continuous monitoring, rather than a one-time scan, does the real work. Because snyk monitor keeps a live record of what's in a project's dependency tree, Snyk can re-evaluate previously approved packages against updated Advisor scores and newly published vulnerability data without requiring a developer to re-run a scan. The colors.js and faker.js incident in January 2022 — where the maintainer intentionally corrupted his own widely used packages in a protest against corporate open source use — is a useful illustration of why this retroactive check matters: teams that had pinned those packages months earlier had no reason to re-scan them manually, and only a monitoring system checking dependencies against live data would have caught the change in status after the fact.
This is also the practical reason deprecation detection needs to be continuous rather than a gate at intake. A package's health score today is not a guarantee about its health score in six months, and the packages most likely to cause an incident are often the ones nobody has looked at again since the day they were added.
How Safeguard Helps
Package health scoring like Snyk's is a strong first layer of defense, but it depends on registry and repository metadata that a determined attacker can obscure, and it stops at the dependency-declaration level — it doesn't see what a package actually does once it's built, installed, and running in your environment. Safeguard is built to pick up where that visibility ends. Rather than relying solely on public activity signals, Safeguard focuses on verifying software supply chain integrity end-to-end: tracking build provenance so teams know exactly how an artifact was produced, generating and continuously reconciling SBOMs against what's actually deployed, and giving security teams policy controls to block or flag components — deprecated, unmaintained, or otherwise risky — before they reach production, not just at the moment a developer runs a scan. For teams that already rely on tools like Snyk to catch known-deprecated and low-maintenance packages early, Safeguard adds the runtime and provenance layer that keeps that protection intact as software moves from a developer's laptop through the build pipeline and into production.