Apache Storm Client: Deserialization of Untrusted Data
CVE-2026-82436 is a high-severity deserialization of untrusted data vulnerability in Apache Storm Client from Apache, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists version 3.1.0 as the first without the flaw, so updating Apache Storm Client to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.57% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Apache Storm Client to 3.1.0 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache Storm Client | 3.0.0 up to, but not including, 3.1.0 | 3.1.0 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
Description `DefaultStateSerializer`, used to persist and restore stateful bolt checkpoints, configured Kryo with class registration disabled and an instantiation strategy that constructs objects without invoking their constructors, then deserialized whatever bytes the state store returned. A party able to write to the topology's keyspace in the state store, for example a co-tenant of a shared Redis instance or anyone with network access to it, could therefore place a serialized object graph that executes code inside the worker JVM when the state is restored. This requires the Redis-backed state provider, which is not the default. Write access to a state-store key is a data-plane privilege; code execution in the worker JVM is not, so the two are not equivalent. Mitigation Upgrade to 3.1.0, where the state serializer requires registered classes. Note that this is a behaviour change for existing state: checkpoints written by an affected version may fail to restore, and a migration step may be required. Users who cannot upgrade immediately should restrict network and credential access to the state store to the cluster itself. Credit The ASF -- found using Claude agents to study the security of open-source projects, validated and reported by Apache Storm.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Deserialization of Untrusted Data
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
How developers prevent this class of flaw
- If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
- When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
- Explicitly define a final object() to prevent deserialization.
More Deserialization of Untrusted Data vulnerabilities (CWE-502)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in Apache Storm Client
- 10.0 Critical severity
- 9.8 Critical severity
- 8.8 High severity
- 8.8 High severity
Recent Deserialization of Untrusted Data vulnerabilities
- 9.8 Critical severity
- 8.8 High severity
- 8.8 High severity
- 7.3 High severity
- 8.8 High severity
- 8.2 High severity
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