CVE-2026-82435: Apache Storm Worker: Unauthenticated Remote Memory Exhaustion in the Worker Messaging Decoder
Description
The worker's Netty message decoder is installed ahead of the SASL authentication handlers in the pipeline and acts on frames before any authentication has taken place. It allocated buffers sized from a length field carried in the frame, so a single frame from an unauthenticated peer able to reach a worker slot port could drive a large allocation.
storm.messaging.netty.authentication defaults to false, and the decoder runs before the handler that enforces it in any case, so no credentials are required. The attacker needs only TCP reachability to a worker port.
The effect of a single frame at the default 768 MB worker heap has not been measured to distinguish sustained worker loss from transient garbage-collection pressure. The severity assigned to this advisory reflects the more conservative reading; consumers who require a precise figure should test against their own worker heap configuration.
Mitigation
Upgrade to 3.1.0, where frames are decoded only after the handshake completes.
Users who cannot upgrade immediately should ensure that worker slot ports are reachable only from within the cluster, as the security model already recommends, and should enable storm.messaging.netty.authentication where the deployment permits it.
Credit
The ASF -- found using Claude agents to study the security of open-source projects, validated and reported by Apache Storm.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Apache Storm Workerto a version that resolves this vulnerability.Fixed in 3.1.0 - Configuration
If you cannot upgrade immediately, ensure worker slot ports are reachable only from within the cluster, so unauthenticated peers cannot send frames; also verify that the deployment permits keeping storm.messaging.netty.authentication at its default of false so the decoder runs before the handler, matching the advisory’s stated mitigation constraints.
Apache Storm (Netty messaging pipeline) storm.messaging.netty.authentication = false - Configuration
In deployments where permitted, enable authentication such that storm.messaging.netty.authentication is enforced before any worker messaging decoder processes frames (the advisory states the decoder is installed ahead of the SASL authentication handlers unless authentication is enforced).
Apache Storm (Netty messaging pipeline) storm.messaging.netty.authentication = true - Compensating control
Restrict network access so worker slot/worker slot ports are reachable only from within the cluster (per the advisory’s security model recommendation).
Event History
Frequently Asked Questions
Which deployments are exposed to this issue?
Any worker whose slot port is reachable by an unauthenticated TCP peer is exposed. The default setting, storm.messaging.netty.authentication, is false, but enabling it does not prevent this issue because decoding occurs before the SASL authentication handler.
What does an attacker need to exploit it?
The attacker needs only TCP network reachability to a worker slot port. No credentials or completed authentication handshake are required.
What can be done if an upgrade is not immediately possible?
Restrict worker slot ports so they are reachable only from within the cluster, consistent with the recommended security model. Enable storm.messaging.netty.authentication as an additional measure, but do not rely on it alone to block this flaw.
What is the expected operational impact?
A single crafted frame can cause a large memory allocation based on its supplied length field. At the default 768 MB worker heap, it has not been measured whether this causes sustained worker loss or only transient garbage-collection pressure; test against the worker heap configuration in use.