Description Dependency artifacts uploaded with `storm jar --artifacts` were stored under a blob key derived only from the Maven coordinate, for example `dep---.jar`. The key was therefore identical for every user of the cluster and predictable in advance. When the blob already existed, the uploader caught `KeyAlreadyExistsException` and silently reused it, with no check that the existing blob's content or owner matched the artifact the submitter had resolved. A user who uploaded a blob under such a key first therefore controlled the bytes that every later submitter of the same coordinate would receive on the worker classpath, resulting in code execution inside another tenant's topology. This affects deployments where more than one principal may create blobs and where the `--artifacts` dependency feature is used. Mitigation Upgrade to 3.1.0, where each uploaded artifact receives a key carrying a freshly generated UUID and a pre-existing blob is no longer silently reused. Note that the corrected key generation is on the SUBMITTING CLIENT, so upgrading the cluster alone does not close this; every client that runs `storm jar --artifacts` must also be upgraded. Operators should audit existing `dep-` blobs for unexpected owners before upgrading. Users who cannot upgrade immediately should avoid the `--artifacts` mechanism in multi-tenant clusters and distribute dependencies inside the topology jar instead. Credit The ASF -- found using Claude agents to study the security of open-source projects, validated and reported by Apache Storm.