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CVE-2026-85058 high CVSS 7.5

Vulnerability in io.moquette:moquette-broker (CVE-2026-85058)

Summary

Vulnerability in io.moquette:moquette-broker (CVE-2026-85058). Data can be tampered with by attackers. Exploitable via receivedPublishQos0. Mitigation: upgrade to 0.18.1 or later.

Original description

The description as published by the source.

Summary

Moquette MQTT Broker fails to enforce ACL write permission checks when publishing Will (Last Will and Testament) messages on behalf of disconnected clients. All normal PUBLISH paths (receivedPublishQos0, receivedPublishQos1, receivedPublishQos2) correctly invoke authorizator.canWrite() before publishing, but the Will message publishing path (fireWill() → publishWill() → publish2Subscribers()) completely bypasses this authorization check.

This allows an unauthenticated attacker (when allow_anonymous=true, which is the default) to inject arbitrary messages into any ACL-protected topic by setting a restricted topic as the Will Topic in the CONNECT packet and then disconnecting abruptly via TCP RST.

Other major MQTT Broker implementations (Mosquitto, EMQX, HiveMQ) correctly enforce ACL checks on Will messages, confirming this is a bug, not a design choice.

Details

In the MQTT protocol, a client can declare a "Will" topic and message in the CONNECT packet. When the client disconnects abnormally (without sending a DISCONNECT packet), the Broker publishes the Will message on behalf of the client. Although the Will message content (topic and payload) is entirely controlled by the connecting client — making it functionally equivalent to a PUBLISH — Moquette skips the ACL check for this path.

Root Cause

File: broker/src/main/java/io/moquette/broker/PostOffice.java (v0.18.0)

Will publishing path (lines 286-328) — no canWrite() check:
`…

Source: NIST National Vulnerability Database NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-85058 has been found in io.moquette:moquette-broker.
Attackers can target a specific entry point like receivedPublishQos0 over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 7.5/10.
What to do: upgrade io.moquette:moquette-broker to 0.18.1 or later.
If unsure, ask your IT team or search "io.moquette:moquette-broker CVE-2026-85058" on the vendor's site.

CVE-2026-85058 (io.moquette:moquette-broker) — CWE-862 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: receivedPublishQos0 / receivedPublishQos1 / receivedPublishQos2 / allow_anonymous
Patched: 0.18.1 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-862) exists in io.moquette:moquette-broker. Attackers reach the vulnerable code path via receivedPublishQos0 without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of io.moquette:moquette-broker. Attack surface: receivedPublishQos0 / receivedPublishQos1 / receivedPublishQos2 / allow_anonymous.

🔥 Severity

Severity: High (CVSS 7.5/10). Data can be tampered with by attackers.

🔧 How to fix

Update to 0.18.1.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    Audit SBOM/dependencies for affected components.

    資産台帳・SBOM・依存マニフェストで io.moquette:moquette-broker を使っているサービスとバージョンを洗い出す。

  2. 2
    Apply patch patch 
    Upgrade io.moquette:moquette-broker to 0.18.1

    ステージング環境で 0.18.1 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  3. 3
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

maven io.moquette:moquette-broker
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.18.1"}]}]

References

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