CVE-2023-42809

What it is

Redisson is a Java Redis client that uses the Netty framework. Prior to version 3.22.0, some of the messages received from the Redis server contain Java objects that the client deserializes without further validation. Attackers that manage to trick clients into communicating with a malicious server can include especially crafted objects in its responses that, once deserialized by the client, force it to execute arbitrary code. This can be abused to take control of the machine the client is running in. Version 3.22.0 contains a patch for this issue. Some post-fix advice is available. Do NOT use `Kryo5Codec` as deserialization codec, as it is still vulnerable to arbitrary object deserialization due to the `setRegistrationRequired(false)` call. On the contrary, `KryoCodec` is safe to use. The fix applied to `SerializationCodec` only consists of adding an optional allowlist of class names, even though making this behavior the default is recommended. When instantiating `SerializationCodec` please use the `SerializationCodec(ClassLoader classLoader, Set<String> allowedClasses)` constructor to restrict the allowed classes for deserialization.

At a glance

Exploitability

Can be exploited over the network without logging in, but needs a user to act. High risk of data exposure, data tampering, service disruption.

Exploit odds

1.1% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2023-10-04 20:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 06:24 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 1.1% in the next 30 days (EPSS).
• Severity: 9.6 CRITICAL (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2023-10-04 20:15 UTC

Last modified

2026-06-17 06:24 UTC

Exploit probability

1.1% · EPSS, next 30 days

Weakness

CWE-502 · Unsafe deserialization

Record status

Modified

Affected

• Redisson < 3.22.0

Attack profile CVSS 3.1 · 9.6

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

Required

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2023-42809.md and follow it. Check whether this project is affected by CVE-2023-42809. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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