# 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.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Sep 2026
- **Updated:** 14 Sep 2026
- **Also known as:** GHSA-5978-3w53-3qhw

## 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.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key), CWE-20 (Improper Input Validation)

## 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.

## Is CVE-2026-82441 being exploited?

There is no known exploitation of CVE-2026-82441 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-82441 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-82441 in the wild and no public exploit code.

Affected product: Apache Storm Nimbus. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-82441/ (Markdown: https://insights.sbomify.com/CVE-2026-82441/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-82441
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-82441
- OSV: https://osv.dev/vulnerability/CVE-2026-82441

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-82441/
Summaries are generated and may contain mistakes; the official description above is the record.