Vulnerability record · CVE-2026-82432 · published 14 September 2026
CVE-2026-82432: Incorrect authorization vulnerability
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.
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.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
References
Track CVE-2026-82432 inside VULONE
Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.
Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2026-82432), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.
