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CVE-2026-107726 — Vulnerability in com.hazelcast:hazelcast — CVE...

CRITICAL

Hazelcast allows arbitrary member memory access by low-privileged client

Published October 8, 2026Updated October 8, 2026Source: osv

Summary

### 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](https://docs.hazelcast.com/hazelcast/5.7/secure-cluster/hardening-recommendations), including: * Ensure [Hazelcast Security](https://docs.hazelcast.com/hazelcast/5.7/security/enable-security) is enabled and [client authorization](https://docs.hazelcast.com/hazelcast/5.7/security/client-authorization) is enforced. * Define an [explicit allowlist for zero config Compact serialization](https://docs.hazelcast.com/hazelcast/5.7/serialization/compact-serialization#zero-config-filter). * 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](https://support.hazelcast.com/s/article/Security-Advisory-GHSA-6v25-8wq6-xq4j)

Advisory Timeline

  • First published October 8, 2026 (3 days ago).
  • Last revised October 8, 2026 — 0 days after initial publication.

Remediation

Upgrade to the fixed version using your package manager.

Maven
Update com.hazelcast:hazelcast to 5.7.0 or later
<!-- Update pom.xml dependency version to 5.7.0 for com.hazelcast:hazelcast -->
Maven
Update com.hazelcast:hazelcast to 5.7.0 or later
<!-- Update pom.xml dependency version to 5.7.0 for com.hazelcast:hazelcast -->
Maven
Update com.hazelcast:hazelcast to 5.7.0 or later
<!-- Update pom.xml dependency version to 5.7.0 for com.hazelcast:hazelcast -->

After upgrading, run your dependency scanner again to confirm the vulnerability is resolved.

Affected Packages (3)

Affects 1 ecosystem: maven (1).

PackageEcosystemAffectedFixed In
com.hazelcast:hazelcast
maven
1.5, 1.5.1, 1.5.2, 1.5.3 (+266 more)5.7.0
com.hazelcast:hazelcast
maven
5.5.0, 5.6.0, 5.6.0-BETA-15.7.0
com.hazelcast:hazelcast
maven
5.6.05.7.0

Vulnerability Classification

Common Weakness Enumeration (CWE) identifiers for this vulnerability type.

  • CWE-20
    Improper Input ValidationMITRE

CVSS Score Breakdown

What the CVSS (Common Vulnerability Scoring System) 9.8 score means for each attack dimension.

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
—
Confidentiality
—
Integrity
—
Availability
—

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Frequently Asked Questions

What is CVE-2026-107726?
Hazelcast allows arbitrary member memory access by low-privileged client This vulnerability has been assigned a severity rating of CRITICAL (CVSS score: 9.8/10).
How do I check if my project is affected by CVE-2026-107726?
CVE-2026-107726 affects com.hazelcast:hazelcast. Use GeekWala's free vulnerability scanner to check your dependencies against CVE-2026-107726 and 200,000+ other known vulnerabilities.

Severity & Exploitability

CVSS Score
9.8

Exploitation is straightforward and causes maximum impact. Patch immediately.

Also Known As

GHSA-6v25-8wq6-xq4j

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