CVE-2026-107726: Hazelcast

Critical severity, CVSS 9.3. EPSS: 0.4% chance of exploitation in the next 30 days.

Hazelcast is a unified real-time data platform combining stream processing with a fast data store. Prior to 5.4.5, 5.5.10, and 5.6.1, improper validation of data supplied by a malicious client able to connect to a cluster allows arbitrary reads from a cluster member's Java heap, off-heap data, and JVM process address space. The same flaw can crash cluster members and, in some Hazelcast Enterprise Edition configurations, corrupt memory with possible arbitrary code execution. Both slim and full distributions are affected. This issue is fixed in versions 5.4.5, 5.5.10, 5.6.1, and 5.7.0.

Affected products

• Hazelcast Hazelcast: before 5.4.5 (fixed in 5.4.5); from 5.5.0, before 5.5.10 (fixed in 5.5.10); from 5.6.0, before 5.6.1 (fixed in 5.6.1)

Published 2026-10-08. Last modified 2026-10-09.