CVE-2026-82441 Apache Storm Nimbus: Cross-Tenant Blob Deletion and Cluster Denial of Service via Unvalidated Topology Dependency Keys
Attackers can delete other tenants' blobs or cause cluster-wide denial of service by submitting topologies with unvalidated dependency keys.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-82441?
CVE-2026-82441 is a critical missing authorization vulnerability in Apache Storm Nimbus, published on 14 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Description
A submitted topology carries two lists of blobstore keys, `dependency_jars` and `dependency_artifacts`, which the client fills in after uploading the corresponding blobs. Nimbus performed no validation of their contents on the submission path, yet acts on them in two places.
During cleanup of a finished topology, Nimbus deletes the keys named in those lists, and the deletion is performed as the Nimbus subject, for which the blobstore short-circuits its ACL check. A submitter who listed a key belonging to another topology, such as its `-stormjar.jar`, could therefore cause that blob to be deleted when their own topology was cleaned up.
Separately, on acquiring leadership a Nimbus compares the dependency keys of all active topologies against the blobstore contents and surrenders leadership if any is missing. A single key that does not exist, on a single active topology, therefore causes every Nimbus to acquire leadership, surrender it and requeue indefinitely, leaving the cluster without a leader and unable to schedule, clean up or accept submissions.
Mitigation
Upgrade to 3.1.0, where a submission is refused unless every entry in both lists is a dependency blob key and exists in the blobstore.
Note that this validates new submissions only; a topology stored by an affected version with an invalid list is unaffected by the upgrade. An operator whose cluster is failing to retain a leader should inspect the Nimbus log for the dependency keys reported as missing and remove or resubmit the topology naming them.
Users who cannot upgrade immediately should restrict topology submission to trusted principals.
Credit
This issue was discovered by rzo1 while investigating an unrelated blobstore defect.
Which versions are affected by CVE-2026-82441?
How do I fix CVE-2026-82441?
No fix has been published for CVE-2026-82441 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-82441 being exploited?
There is no known exploitation of CVE-2026-82441 in the wild and no public exploit code.
Sources
Also known as GHSA-5978-3w53-3qhw.