Convoy is a cloud native webhooks gateway. Prior to 26.6.8, Convoy's GET /api/v1/projects/{projectID}/sources/{sourceID} endpoint authorizes access to the project in the URL, but Handler.GetSource calls sources.Service.FindSourceByID() and fetches the Source only by sourceID without confirming that its ProjectID matches the authorized project. An authenticated user or project-scoped API key holder can substitute another tenant's Source identifier and receive that Source's complete record, including unredacted AMQP, Kafka, SQS, or Google PubSub credentials. The list endpoint remains project-scoped; the single-item Source lookup is affected. This issue is fixed in version 26.6.8.

Affected: Go: github.com/frain-dev/convoy

## Summary frain-dev/convoy (all versions up to and including v26.6.2, no patch available) lets any authenticated caller who is authorized on at least one project read ANY OTHER project's "Source" record by ID via GET /api/v1/projects/{projectID}/sources/{sourceID} -- regardless of whether that Source actually belongs to the project named in the URL. The response includes the Source's full PubSub broker configuration in plaintext (AMQP/Kafka/SQS/Google credentials), with no redaction.

## Details `Handler.GetSource` (api/handlers/source.go) resolves the caller's authorization against the {projectID} in the URL via retrieveProject(), then calls `sources.Service.FindSourceByID(ctx, project.UID, sourceID)` (internal/sources/impl.go). That function accepts a projectID parameter but never uses it:

func (s *Service) FindSourceByID(ctx context.Context, projectID, id string) (*datastore.Source, error) { row, err := s.repo.FetchSourceByID(ctx, common.StringToPgText(id)) ... }

The underlying SQL query (internal/sources/repo/queries.sql, `fetchSourceByID`) has no project_id predicate at all:

SELECT ... FROM convoy.sources AS s LEFT JOIN convoy.source_verifiers sv ON s.source_verifier_id = sv.id WHERE s.id = $1 AND s.deleted_at IS NULL

So the {projectID} in the URL only gates "is the caller authorized to view *a* project" -- it never re-validates that the fetched Source actually belongs to that project. `LoadSourcesPaged` (the list endpoint) does…