A scanner reports what has package metadata, and no more

An image scanner identifies packages from manifests, so anything installed by a shell pipe or copied in as a binary is invisible to it.

$ trivy image app:2022-04-11
Total: 14 (HIGH: 3, CRITICAL: 1)

# found:     apk/dpkg packages, composer.lock, package-lock
# not found:
#   a binary fetched by RUN curl ... | sh
#   a jar bundled inside another artefact
#   a vendored library COPYed in with no manifest
#   anything mounted at runtime

A green scan means “nothing in the parts I can identify”, and writing that sentence next to the scan output is what stops it being read as “no vulnerabilities”. The other half is alert volume: a policy that only fails on high severities with a fix available is what keeps anybody reading the result at all.