CVE-2026-82431
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk40th percentile - higher than 40% of all known CVEs
Summary
In Apache Storm's SimpleACLAuthorizer, authorization returned early when nimbus.users was empty, skipping evaluation of nimbus.groups. As a result, a cluster restricted by group alone allowed every authenticated principal to perform all user-level operations, including submitTopology, beginFileUpload and getNimbusConf. The issue is fixed in version 3.1.0.
Risk Assessment
Organizations that restricted cluster access using only nimbus.groups were effectively fully open to all authenticated principals, potentially allowing unauthorized topology submission and access to cluster configuration. The failure is silent — logs and configuration give no indication that the group list is being ignored.
Recommendation
Upgrade Apache Storm to version 3.1.0, where nimbus.groups is evaluated regardless of nimbus.users. If immediate upgrade is not possible, additionally populate nimbus.users with the intended principals and review Nimbus access logs for operations by principals outside the intended groups.
Other vulnerabilities in Apache Storm
See all- CVE-2014-0115High
Directory traversal vulnerability in the log viewer in Apache Storm 0.9.0.1 allows remote attackers to read arbitrary files via a .. (dot dot) in the file parameter to log.
- CVE-2026-82435Critical
In Apache Storm before 3.1.0, a vulnerability exists: the Netty decoder is installed before authentication and processes frames without verification, allowing an unauthenticated attacker to allocate large buffers and potentially cause memory pressure on workers.
- CVE-2026-82441Critical
A vulnerability in Apache Storm allows a topology submitter to delete blobs belonging to other topologies by listing their keys in `dependency_jars` and `dependency_artifacts`. Additionally, missing validation can cause Nimbus to fail to retain leadership, rendering the cluster inoperative.
- CVE-2026-82439Critical
The DRPC server in Apache Storm keeps a map from function names to request queues, and entries are never removed. An attacker can send arbitrary function names without authentication (as `drpc.authorizer` is disabled by default), leading to unbounded memory growth and eventual heap exhaustion.
- CVE-2015-3188Critical
The UI daemon in Apache Storm 0.10.0 before 0.10.0-beta1 allows remote attackers to execute arbitrary code via unspecified vectors.
- CVE-2026-82438High
Three separate mechanisms in Apache Storm's HTTP components allowed a web page on an unrelated origin to read responses served to an authenticated user. The Logviewer reflected the request's Origin header in Access-Control-Allow-Origin while also sending Access-Control-Allow-Credentials: true, the shared CORS filter was misconfigured (a response header name was supplied where an initialisation parameter name was expected, so the container applied its own credential-allowing defaults), and the UI and Logviewer wrapped API responses in a caller-supplied JSONP callback for every GET request. In each case, a page visited by an authenticated operator can read cluster, topology and log data on their behalf.
- CVE-2026-82434Medium
When ZooKeeper authentication is configured, Storm deliberately retains storm.zookeeper.topology.auth.payload in the topology configuration, and Nimbus serves that configuration to any caller with read-only topology permissions. A user granted only topology view access receives the ZooKeeper credential, which is write-capable and allows forging or removing topology state. The credential also reaches logs (INFO in the submission client, DEBUG in SASL handlers), and version 3.1.0 removes it from the served configuration and logs.
- CVE-2026-82433Medium
In Apache Storm before 3.1.0, the getNimbusConf function returns full configuration without redaction, and the UI endpoint /api/v1/cluster/configuration lacks proper authorization, potentially exposing passwords and keys.
- CVE-2026-82432High
In Apache Storm before 3.1.0, the rebalance operation does not revalidate the blobstore map for permissions, and listBlobs lacks authorization checks, allowing an authorized user to access disallowed blobs and disclose metadata.
- CVE-2026-82430High
In CVE-2026-82430 in Apache Storm, the setuid-root `worker-launcher` first changes ownership of the entire worker directory to the untrusted topology user and only afterwards reads the command file written into that directory. The file is opened without `O_NOFOLLOW` and without re-verifying its owner, so the tenant can replace its contents in the window between the ownership change and the read. On the Docker path the rewritten command is executed with real uid 0, and on the OCI path arbitrary host paths can be bind-mounted read-write into the container.
Original NVD description (English source)
Description `SimpleACLAuthorizer` evaluated the user-level command set by returning early when `nimbus.users` was empty, before `nimbus.groups` was considered. An operator who restricted cluster access by group alone, leaving `nimbus.users` unset, therefore received no restriction at all: every authenticated principal was permitted every user-level operation, including `submitTopology`, `beginFileUpload` and `getNimbusConf`. `docs/SECURITY.md` presents `nimbus.groups` as a supported way to lock down a cluster, so a deployment following the documentation could believe it was restricted while it was not. The failure is silent; nothing in the logs or the configuration indicates that the group list is being ignored. Both lists left empty continues to mean that no restriction is configured, which is the shipped default and is unchanged. Mitigation Upgrade to 3.1.0, where `nimbus.groups` is evaluated whether or not `nimbus.users` is set. Users who cannot upgrade immediately should additionally populate `nimbus.users` with the intended principals, since a non-empty user list causes the group list to be evaluated on affected versions. Operators should review Nimbus access logs for operations by principals outside the intended groups. Note that after upgrading, a cluster configured with `nimbus.groups` alone becomes restrictive for the first time. This includes `NimbusClient`, which calls `getLeader` on every connection, so clients outside the configured groups will begin to be refused. Credit The ASF -- found using Claude agents to study the security of open-source projects, validated and reported by Apache Storm.

