# CVE-2026-82432: Apache Storm Nimbus: Blobstore Authorization Bypass via Rebalance Configuration Overrides

> Attackers can bypass blobstore authorization via rebalance overrides or list all blobs, exposing sensitive data in Apache Storm Nimbus.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Sep 2026
- **Updated:** 14 Sep 2026
- **Also known as:** GHSA-hw7r-wm97-cf8j

## What is CVE-2026-82432?

CVE-2026-82432 is a high-severity missing authorization vulnerability in Apache Storm Nimbus, published on 14 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Description

Nimbus validated `topology.blobstore.map` against the calling subject at submission time only. The rebalance
operation accepts configuration overrides and stripped a small set of keys from them, but never re-ran that
validation, so a caller authorised to rebalance a topology could introduce a blobstore map entry naming a
blob whose ACL does not grant them access. Supervisors localise whatever key the map names, placing the
blob's contents into the topology's working directory.

The same advisory covers `listBlobs`, which performed no authorization check and passed no subject, unlike
the neighbouring `getBlobMeta` and `beginBlobDownload` operations. It therefore returned every key in the
blobstore to any caller able to reach the Nimbus Thrift port, which provides the key names that make the
above practical. On its own the disclosure is metadata only.

Mitigation

Upgrade to 3.1.0, where rebalance configuration overrides are validated exactly as submission-time
configuration is, against the rebalancing caller, and where `listBlobs` applies the configured
authorization.

Users who cannot upgrade immediately should restrict rebalance rights to trusted principals, keeping in mind
that membership of a topology's `topology.users` or `topology.groups` confers them.

Credit

The ASF -- found using Claude agents to study the security of open-source projects, validated and reported by Apache Storm.

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2026-82432?


## How do I fix CVE-2026-82432?

No fix has been published for CVE-2026-82432 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-82432 being exploited?

There is no known exploitation of CVE-2026-82432 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-82432 and fix it if it is affected.

What it is: CVE-2026-82432 is a high-severity missing authorization vulnerability in Apache Storm Nimbus, published on 14 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-82432 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-2026-82432/ (Markdown: https://insights.sbomify.com/CVE-2026-82432/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-82432
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-82432
- OSV: https://osv.dev/vulnerability/CVE-2026-82432

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-82432/
Summaries are generated and may contain mistakes; the official description above is the record.