How severe is CVE-2026-107726?

No CVSS score has been assigned to CVE-2026-107726 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-107726?

CVE-2026-107726 affects the following packages: com.hazelcast:hazelcast (Maven), com.hazelcast:hazelcast (Maven), com.hazelcast:hazelcast (Maven). Ecosystems affected: Maven.

How do I fix CVE-2026-107726?

Update com.hazelcast:hazelcast to 5.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-107726 is resolved across your whole dependency graph.

How do I detect CVE-2026-107726 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.hazelcast:hazelcast, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-107726 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-107726 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-107726 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-107726?

CVE-2026-107726 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 31th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-107726?

CVE-2026-107726 is classified as Improper Input Validation (CWE-20). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-107726 published, and has it been updated?

CVE-2026-107726 was published on October 8, 2026 and was last updated on October 21, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕ Maven

Not in CISA KEV

CVE-2026-107726 — hazelcast

Fix: hazelcast/hazelcast@361979d

CVE-2026-107726 is a Improper Input Validation vulnerability in com.hazelcast:hazelcast. A fix is available for com.hazelcast:hazelcast — see the affected versions and patch details below.

Hazelcast: Arbitrary member memory access by low-privileged client

Also known asGHSA-6v25-8wq6-xq4j

Published

Oct 8, 2026

Updated

Oct 21, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Oct 22, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-107726.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs31th percentile — riskier than 31% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

3 pkgs affected

☕com.hazelcast:hazelcast☕com.hazelcast:hazelcast☕com.hazelcast:hazelcast

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

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 Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`com.hazelcast:hazelcast`	≥ 5.6.0&&< 5.7.0	5.7.0`com.hazelcast:hazelcast:5.7.0`
☕Maven	`com.hazelcast:hazelcast`	≥ 5.5.0&&< 5.7.0	5.7.0`com.hazelcast:hazelcast:5.7.0`
☕Maven	`com.hazelcast:hazelcast`	all versions	5.7.0`com.hazelcast:hazelcast:5.7.0`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.hazelcast:hazelcast, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update com.hazelcast:hazelcast to 5.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-107726 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

This vulnerability is rated as Important severity for Red Hat products because an attacker with network connectivity to a cluster member can remotely access process memory, crash cluster instances, or potentially execute arbitrary code without requiring elevated privileges. Any compromised application or client…

Workaround published by Red Hat

Restrict network connectivity to Hazelcast cluster member communication ports (default TCP 5701 through 5708) using firewall rules so that only verified, trusted client systems can establish connections.

Source: Red Hat security advisory for CVE-2026-107726 (CC BY 4.0)

Frequently Asked Questions

### 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

O3 Security · Impact-Aware SCA

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