---
title: "CVE-2026-107726: Hazelcast allows arbitrary member memory access by low-privileged client"
url: https://erroneo.us/security/cve/CVE-2026-107726/
description: "CVE-2026-107726 (com.hazelcast:hazelcast (Maven)): Hazelcast is a unified real-time data platform combining stream processing with a fast data store. Prior…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-10-08
date_modified: 2026-10-09
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-107726"
kev: false
cvss: 9.3
epss: 0.00383
license: All rights reserved. Quote with attribution and a link.
---

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

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.4% , percentile 31: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 31% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes com.hazelcast:hazelcast (Maven) = 5.6.0, fixed in 5.7.0 ; com.hazelcast:hazelcast (Maven) >= 5.5.0, < 5.5.10, fixed in 5.7.0 ; com.hazelcast:hazelcast (Maven) < 5.4.5, fixed in 5.7.0 . Check your lockfile, including transitive dependencies.

## What it is

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 packages

- Maven `com.hazelcast:hazelcast` = 5.6.0 → fixed: 5.7.0
- Maven `com.hazelcast:hazelcast` >= 5.5.0, < 5.5.10 → fixed: 5.7.0
- Maven `com.hazelcast:hazelcast` < 5.4.5 → fixed: 5.7.0

## Affected products (CVE record)

- hazelcast hazelcast: < 5.4.5, >= 5.5.0, < 5.5.10, >= 5.6.0, < 5.6.1

## Severity

- GitHub_M CVSS 4.0: 9.3 `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`
- GitHub CVSS 4.0: 9.3 `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`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.38% probability of exploitation activity in the next 30 days; percentile 31.

## Sources

- [GitHub Advisory GHSA-6v25-8wq6-xq4j](https://github.com/advisories/GHSA-6v25-8wq6-xq4j)
- [CVE.org record CVE-2026-107726](https://www.cve.org/CVERecord?id=CVE-2026-107726)
- [NVD entry CVE-2026-107726](https://nvd.nist.gov/vuln/detail/CVE-2026-107726)
- [github.com](https://github.com/hazelcast/hazelcast/security/advisories/GHSA-6v25-8wq6-xq4j)
- [github.com](https://github.com/hazelcast/hazelcast/commit/361979da12f18950c24719db832ca6c5e7c0534f)
- [docs.hazelcast.com](https://docs.hazelcast.com/hazelcast/5.7/release-notes/community)
- [docs.hazelcast.com](https://docs.hazelcast.com/hazelcast/5.7/release-notes/enterprise)
- [github.com](https://github.com/hazelcast/hazelcast/releases/tag/v5.7.0)

---
Source page: https://erroneo.us/security/cve/CVE-2026-107726/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt