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.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
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
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.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-82432 being exploited?
There is no known exploitation of CVE-2026-82432 in the wild and no public exploit code.
Sources
Also known as GHSA-hw7r-wm97-cf8j.