GHSA-6v25-8wq6-xq4j: Input Validation
Impact
A flaw has been found in Hazelcast Enterprise Edition and Community Edition, which would allow a low-privileged malicious client to read arbitrary data in memory from any cluster member (including Java heap memory, off-heap data, and JVM process address space). Additionally, such a client may be able to cause one or more cluster members to crash, or in some Enterprise Edition configurations also corrupt memory contents, potentially leading to remote code execution. Both slim and full distributions are affected.
Patches
Enterprise customers should upgrade to a fixed version of Hazelcast Enterprise Edition: 5.7.0 5.6.1 5.5.10 5.4.5 Customers with extended support contracts should contact Hazelcast Support for information on patches for older versions.
Community Edition users should upgrade to version 5.7.0.
Hazelcast also recommends all customers follow the advice in our Security Hardening guide, including:
Ensure Hazelcast Security is enabled and client authorization is enforced. Define an explicit allowlist for zero config Compact serialization. Avoid deploying clients on internet-facing non-secure networks or non-secure hosts. Ensure your Hazelcast cluster is appropriately protected by firewall rules. Disable any features you are not using.
Workarounds If you cannot update to a fixed version immediately, restrict cluster access to trusted clients only and ensure clients are hardened against compromise.
References
Security Advisory on the Hazelcast Support Portal
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
maven/com.hazelcast:hazelcastto a version that resolves this vulnerability.Fixed in 5.7.0 - Upgrade
Upgrade
Hazelcast Community Editionto a version that resolves this vulnerability.Fixed in 5.7.0 - Upgrade
Upgrade
Hazelcast Enterprise Editionto a version that resolves this vulnerability.Fixed in 5.4.5 - Upgrade
Upgrade
Hazelcast Enterprise Editionto a version that resolves this vulnerability.Fixed in 5.5.10 - Upgrade
Upgrade
Hazelcast Enterprise Editionto a version that resolves this vulnerability.Fixed in 5.6.1 - Upgrade
Upgrade
Hazelcast Enterprise Editionto a version that resolves this vulnerability.Fixed in 5.7.0 - Configuration
Define an explicit allowlist for zero config Compact serialization.
Hazelcast zero config Compact serialization allowlist = explicit allowlist - Configuration
Disable any Hazelcast features that are not being used.
Hazelcast unused features = disabled - Configuration
Ensure Hazelcast Security is enabled and client authorization is enforced.
Hazelcast Security and client authorization security and client authorization = enabled and enforced - Compensating control
Avoid deploying clients on internet-facing non-secure networks or non-secure hosts, restrict cluster access to trusted clients only, and protect the Hazelcast cluster with firewall rules.
Event History
Frequently Asked Questions
Which deployments are affected?
Both Hazelcast Enterprise Edition and Community Edition are affected, including both slim and full distributions. Exploitation requires a malicious client with low privileges.
What should be prioritized for remediation?
Enterprise Edition customers should upgrade to 5.7.0, 5.6.1, 5.5.10, or 5.4.5. Community Edition users should upgrade to 5.7.0; customers using older Enterprise versions under extended support should contact Hazelcast Support for patch information.
What can reduce exposure before an upgrade is completed?
Enable Hazelcast Security and client authorization, and apply the vendor's security hardening recommendations. These measures are particularly important because a low-privileged client can read arbitrary memory and may crash cluster members; some Enterprise configurations may also permit memory corruption.