CVE-2026-82432

Apache Storm Nimbus: Blobstore Authorization Bypass via Rebalance Configuration Overrides

Published Sep 14, 2026 CVSS 3.1 · 8.1 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Apache
Apache storm Nimbus
Vendors & Products Apache
Apache storm Nimbus
Type Values Removed Values Added
Metrics ssvc

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

Type Values Removed Values Added
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N'}

Type Values Removed Values Added
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.
Title Apache Storm Nimbus: Blobstore Authorization Bypass via Rebalance Configuration Overrides
Weaknesses CWE-863
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
apache
Published
Updated
Sep 14, 2026, 8:03 PM
Reserved
Aug 29, 2026, 10:23 AM
Status
Deferred
Published
Sep 14, 2026, 3:17 PM
Modified
Sep 14, 2026, 8:58 PM