CVE-2026-82440
| Severity | 8.1 High CVSS 3.1 |
|---|---|
| Weakness | Unsafe reflection (CWE-470) |
| Published | 9 Nov 2026 |
| Updated | 12 Nov 2026 |
Published 4 days ago. NVD often adds the list of affected products days or weeks after a CVE is published, and the other sources we check lag too. The scope and status here may change.
Description
Description
Nimbus instantiates the class named by a topology's topology.scheduler.strategy when scheduling it. The
allowlist intended to constrain that choice, nimbus.scheduler.strategy.class.whitelist, was treated as
"allow any class" when unset, and it had no entry in the shipped defaults.yaml, so unset was the shipped
state. An authenticated submitter could therefore cause Nimbus to instantiate any class on the Nimbus
classpath that has a no-argument constructor.
Storm's own production artifacts contain classes with side effects suitable for this: instantiating
org.apache.storm.testing.InProcessZookeeper starts a ZooKeeper server with its own threads and sockets
and nothing closes it, and org.apache.storm.LocalCluster behaves similarly. Repeated submissions
therefore consume threads, sockets and memory in the most privileged daemon in the cluster.
Mitigation
Upgrade to 3.1.0, where an unset allowlist means the strategies shipped with Storm rather than any class.
Note that this is a behaviour change: a cluster running an out-of-tree scheduler strategy without an
explicit allowlist will have those topologies refused until the class is added to
nimbus.scheduler.strategy.class.whitelist. The rejection message names the refused class and the
configuration key.
Users who cannot upgrade immediately should set nimbus.scheduler.strategy.class.whitelist explicitly to
the strategies they intend to permit.
Exploitation status
No public exploit
No exploit has been reported in the sources we check.
Exploitation status
- CISA KEV not listed
- VulnCheck KEV not listed
- CISA Vulnrichment exploitation: none
- Indexed PoC none indexed
- EPSS 0.45% chance in 30 days
Waratek protection
Waratek has a rule that blocks attacks on this vulnerability.
- Protection full Reflection
- Action available security rule
- Review automated Inferred
- Record active
| Decided by | A vulnerability class already blocked by an ARMR security rule |
|---|---|
| Finding | Protected by Waratek's ARMR reflection security rule, which blocks this class of attack at the JVM level without a rule written for this CVE specifically. The CVE's weakness is CWE-470: Unsafe Reflection. |
How to mitigate CVE-2026-82440
Apply the vendor's fix. Until you can, Waratek RASP blocks exploitation with its reflection rule. It runs inside the Java application, with no code changes.
References
| URL | Tags |
|---|---|
| https://lists.apache.org/thread.html/hxcyk1vg9qx8bzos8g3kx91nz8d23jgt | |
| http://www.openwall.com/lists/oss-security/2026/11/09/2 |
Timeline
Timeline
| Published | 2026-11-09 | By the CVE Program. |
|---|---|---|
| NVD record modified | 2026-11-12 | NVD's own last-modified date for this record. |