Apache Storm Nimbus vulnerability allows submitter-controlled class instantiation
Apache Storm Nimbus before 3.1.0 treats unset scheduler strategy whitelist as allow any class, enabling arbitrary class instantiation.
40
CVE-2026-82440
Submitter-Controlled Class Instantiation in Apache Storm Nimbus
- CVSS
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- EPSS
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- Published
- ·
- Modified
AI analysisSummaries by Vani AI
An authenticated submitter of a Storm topology can cause Nimbus to instantiate any class on the classpath that has a no-argument constructor by specifying an unrestricted scheduler strategy. This allows starting services like ZooKeeper servers that consume threads, sockets, and memory in the privileged Nimbus daemon. Apache Storm users with versions prior to 3.1.0 are affected.
What to do: Upgrade to Storm 3.1.0. Set nimbus.scheduler.strategy.class.whitelist to limit allowed classes.
| Product | Affected | Fixed in |
|---|---|---|
| Apache Storm | prior to 3.1.0 | 3.1.0 |
Estimated exposure
No basis for an estimate.
Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.
Description · NVD
Description Nimbus instantiates the class named by a topology's `topology.scheduler.strategy` when scheduling it. The allowlist intended to constrain that choice, `nimbus.scheduler.strategy.class.whitelist`, was treated as "allow any class" when unset, and it had no entry in the shipped `defaults.yaml`, so unset was the shipped state. An authenticated submitter could therefore cause Nimbus to instantiate any class on the Nimbus classpath that has a no-argument constructor. Storm's own production artifacts contain classes with side effects suitable for this: instantiating `org.apache.storm.testing.InProcessZookeeper` starts a ZooKeeper server with its own threads and sockets and nothing closes it, and `org.apache.storm.LocalCluster` behaves similarly. Repeated submissions therefore consume threads, sockets and memory in the most privileged daemon in the cluster. Mitigation Upgrade to 3.1.0, where an unset allowlist means the strategies shipped with Storm rather than any class. Note that this is a behaviour change: a cluster running an out-of-tree scheduler strategy without an explicit allowlist will have those topologies refused until the class is added to `nimbus.scheduler.strategy.class.whitelist`. The rejection message names the refused class and the configuration key. Users who cannot upgrade immediately should set `nimbus.scheduler.strategy.class.whitelist` explicitly to the strategies they intend to permit.
- Weakness
- CWE-470