CVE-2026-82436: Insecure Deserialization (CVSS 8.8)

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.

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CVSS v3.1 Score

8.8

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0027

Probability of exploitation

0.19%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-502 Deserialization of Untrusted Data

References

Other References

https://lists.apache.org/thread.html/q5vqclkjdvngwkffcbwbwyym410sp8sc http://www.openwall.com/lists/oss-security/2026/11/09/1

Frequently Asked Questions

What is CVE-2026-82436? +

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. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2026-82436? +

CVE-2026-82436 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0027, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-82436? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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