Description
Description

Nimbus accepted the `uploadedJarLocation` argument of `submitTopology` / `submitTopologyWithOpts` as a
server-side path and opened it directly, without checking that it referred to a file the caller had
actually uploaded. The intended flow is that a client first calls `beginFileUpload`, which returns a path
inside the Nimbus inbox, and uploads the jar in chunks to that location; nothing bound submission to that
flow, and the `uploaders` map populated by `beginFileUpload` was never consulted at submit time.

An authenticated user with topology submission rights could therefore submit any path readable by the
Nimbus daemon user as their topology jar. Nimbus copied the file into the topology's jar blob, and the
blob ACL grants the submitting subject read access, so the contents could then be retrieved with the
ordinary blob download RPCs. Candidate targets include the Nimbus Kerberos keytab, Thrift and UI TLS
private keys, and `storm.yaml` with the ZooKeeper authentication payload. Possession of the Nimbus keytab
turns an ordinary tenant into a cluster administrator.

In a deployment configured as the documentation recommends, submission is available to every
authenticated principal when `nimbus.users` is unset, so no elevated privilege is required.

Mitigation

Upgrade to 3.1.0, where the submitted location is canonicalised and must resolve inside the Nimbus inbox.

Users who cannot upgrade immediately should restrict topology submission to trusted principals via
`nimbus.users` or `nimbus.groups`, and should treat any file readable by the Nimbus daemon user as
potentially exposed to submitters: rotate the Nimbus keytab and any TLS private keys or ZooKeeper
credentials reachable from that account. Local mode is unaffected.


Credit

Independently reported to the Apache Storm PMC by n0mi1k, with a proof of concept.

Also found by the ASF using Claude agents to study the security of open-source projects, validated and reported by Apache Storm.
Published: 2026-09-14
Score: 6.5 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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Tracking

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Advisories

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History

Mon, 14 Sep 2026 21:00:00 +0000

Type Values Removed Values Added
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 14 Sep 2026 14:30:00 +0000

Type Values Removed Values Added
Description Description Nimbus accepted the `uploadedJarLocation` argument of `submitTopology` / `submitTopologyWithOpts` as a server-side path and opened it directly, without checking that it referred to a file the caller had actually uploaded. The intended flow is that a client first calls `beginFileUpload`, which returns a path inside the Nimbus inbox, and uploads the jar in chunks to that location; nothing bound submission to that flow, and the `uploaders` map populated by `beginFileUpload` was never consulted at submit time. An authenticated user with topology submission rights could therefore submit any path readable by the Nimbus daemon user as their topology jar. Nimbus copied the file into the topology's jar blob, and the blob ACL grants the submitting subject read access, so the contents could then be retrieved with the ordinary blob download RPCs. Candidate targets include the Nimbus Kerberos keytab, Thrift and UI TLS private keys, and `storm.yaml` with the ZooKeeper authentication payload. Possession of the Nimbus keytab turns an ordinary tenant into a cluster administrator. In a deployment configured as the documentation recommends, submission is available to every authenticated principal when `nimbus.users` is unset, so no elevated privilege is required. Mitigation Upgrade to 3.1.0, where the submitted location is canonicalised and must resolve inside the Nimbus inbox. Users who cannot upgrade immediately should restrict topology submission to trusted principals via `nimbus.users` or `nimbus.groups`, and should treat any file readable by the Nimbus daemon user as potentially exposed to submitters: rotate the Nimbus keytab and any TLS private keys or ZooKeeper credentials reachable from that account. Local mode is unaffected. Credit Independently reported to the Apache Storm PMC by n0mi1k, with a proof of concept. Also found by the ASF using Claude agents to study the security of open-source projects, validated and reported by Apache Storm.
Title Apache Storm Nimbus: Arbitrary File Read on Nimbus via Unvalidated Uploaded Jar Location
Weaknesses CWE-22
References

Subscriptions

No data.

cve-icon MITRE

Status: PUBLISHED

Assigner: apache

Published:

Updated: 2026-09-14T19:53:45.290Z

Reserved: 2026-08-29T10:01:40.256Z

Link: CVE-2026-82426

cve-icon Vulnrichment

Updated: 2026-09-14T14:13:17.028Z

cve-icon NVD

Status : Deferred

Published: 2026-09-14T15:17:09.410

Modified: 2026-09-14T20:58:48.430

Link: CVE-2026-82426

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-22

    Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')