Dependency Audit

Dependency Audit

Intro

Third-party dependencies are the largest part of most codebases' attack surface. A dependency audit runs the ecosystem's vulnerability scanner, triages findings by severity, and produces a concrete update plan.

Overview

Run the right tool

Each ecosystem ships its own audit command:

Install the tool if it's missing (e.g. cargo install cargo-audit), then run it from the project root with the lockfile present.

Triage by severity

• Critical / High — fix immediately. Update or replace the dependency before merging anything else.
• Medium — schedule a fix within the current sprint.
• Low — track and address when convenient.

For each finding, check whether a patched version exists, whether the vulnerable code path is actually reached, and whether a workaround (config, version pin) buys time.

Update strategy

• Update one dependency at a time so breakage is easy to attribute.
• Run the full test suite after each update.
• Read changelogs before any major version bump.
• Use lockfiles to pin exact versions across environments.

Ongoing maintenance

• Schedule monthly dependency reviews on the calendar.
• Enable Dependabot, Renovate, or equivalent for automated update PRs.
• Document any deliberately pinned versions inline with the reason.

Gotchas

Agent-specific failure modes — provider-neutral pause-and-self-check items:

• Running the audit once and never repeating it. Vulnerabilities are added to advisory databases daily. A clean audit today may have critical findings tomorrow. Schedule monthly audits and integrate the scanner into CI.
• Conflating audit with outdated check. The vulnerability scanner (cargo audit, npm audit) catches known CVEs in current versions. The outdated checker (cargo outdated, npm outdated) flags stale packages. They answer different questions and should both run.
• Auto-merging Dependabot PRs without running tests. A Dependabot PR can introduce a breaking API change even in a patch bump. Require CI to pass and spot-check major bumps manually before merging.
• Treating "0 vulnerabilities" as proof of security. Known-CVE scans miss typosquatting, abandoned maintainers, license risks, and malicious updates. A clean audit is a necessary condition, not a sufficient one.
• Suppressing findings without documenting the reason. Future auditors cannot tell whether a suppressed advisory was intentional or forgotten. Every ignore rule needs a rationale and an expiry date.
• Batching many dependency updates into one PR. When a multi-update PR breaks something, you cannot attribute the breakage to the specific dependency. Update one dependency at a time, run the tests, then merge.
• Treating a major version bump the same as a patch bump. Major bumps require changelog review for breaking changes before merging. A quick major-bump merge is how silent regressions reach production.

Full reference

What "audit" actually checks

Audit tools cross-reference the lockfile against vulnerability databases (RustSec, OSV, GitHub Advisory, npm advisory). They report direct and transitive dependencies, but they only catch known vulnerabilities — a clean audit is not the same as a secure dependency tree.

When the fix isn't trivial

• No patched version exists. Pin the current version, file an upstream issue, and look for an alternative library. Document the acceptance in the lockfile or a SECURITY.md exception list.
• Patched version is a major bump. Branch off, run the upgrade in isolation, and address breaking changes before merging.
• Vulnerability is in a transitive dep. Force-resolve the transitive version (npm overrides, pnpm overrides, Cargo [patch], pip constraints) until the parent dependency catches up.
• The vulnerable code path is unreachable in your usage. Note the rationale alongside the suppression. Do not silently ignore.

Anti-patterns

• Running the audit once and never again.
• Bumping a dozen dependencies in a single PR.
• Suppressing findings without writing down the reason.
• Trusting "0 vulnerabilities" as proof of security — supply-chain risk extends beyond known CVEs (typosquats, malicious updates, abandoned maintainers).
• Auto-merging Dependabot PRs without running tests.

Output expectations

A useful audit summary identifies the package manager, lists each vulnerable dependency with its severity and recommended fix, calls out anything without a maintained alternative, and proposes a single ordered update sequence.