How severe is CVE-2026-95842?

No CVSS score has been assigned to CVE-2026-95842 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-95842?

CVE-2026-95842 affects the following packages: io.moquette:moquette-broker (Maven). Ecosystems affected: Maven.

How do I fix CVE-2026-95842?

Update io.moquette:moquette-broker to 0.18.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-95842 is resolved across your whole dependency graph.

How do I detect CVE-2026-95842 in my Maven dependencies?

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

How do I mitigate CVE-2026-95842 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.

How does O3 Security protect against CVE-2026-95842?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-95842 can be triaged on real exposure rather than presence alone.

Is CVE-2026-95842 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-95842 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-2026-95842?

CVE-2026-95842 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 30th 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-2026-95842?

CVE-2026-95842 is classified as CWE-248 (CWE-248). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-95842 published, and has it been updated?

CVE-2026-95842 was published on September 23, 2026 and was last updated on September 25, 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-2026-95842 — moquette-broker

Fix: moquette-io/moquette@86feb7c

CVE-2026-95842 is a CWE-248 vulnerability in io.moquette:moquette-broker. A fix is available for io.moquette:moquette-broker — see the affected versions and patch details below.

Moquette uncaught MQTT command exceptions can terminate shared session event loops

Also known asCVE-2026-85724 CVE-2026-95843 CVE-2026-95844 CVE-2026-95845 CVE-2026-95846 CVE-2026-95847

Published

Sep 23, 2026

Updated

Sep 25, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 25, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-95842.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs30th percentile — riskier than 30% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

1 pkg affected

☕io.moquette:moquette-broker

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

What a connecting client can do

(Critical) Bypass pattern-based ACLs across tenants. In AuthorizationsCollector.canDoOperation (AuthorizationsCollector.java:116-131, esp. line 123) the clientId/username is substituted raw into a pattern ACL rule and then wildcard-matched, and the clientId is never validated for MQTT wildcard characters +/# at CONNECT (MQTTConnection.processConnect):

Topic substitutedTopic = new Topic(auth.topic.toString().replace("%c", client).replace("%u", username)); if (topic.match(substitutedTopic)) return true;

A client that connects with clientId + turns sensor/%c/# into the filter sensor/+/#, gaining cross-tenant read AND write. (Precondition: pattern ACL rules configured — a common multi-tenant setup.)

(High) Crash the whole broker. SessionEventLoop (SessionEventLoop.java:40-54) catches only InterruptedException and is never restarted (SessionEventLoopGroup), so any uncaught exception on it wedges every co-located client. Trivially reachable inputs: malformed $share/grp SUBSCRIBE (SharedSubscriptionUtils.extractShareName -> StringIndexOutOfBoundsException), deeply nested topic (CTrie recursion -> StackOverflowError), and ACL NPE below. Unbounded subscriptions / retained / in-flight / topic-alias / interceptor state (BrokerInterceptor uses an unbounded queue) also allow OOM; durable stores allow disk exhaustion.
(High) NPE in ACL sink on clientId # (invalid filter sensor/#/# -> null tokens -> Topic.match NPE at Topic.java:173).
(High) Will-message authorization bypass. Last-Will topic is published (PostOffice.publishWill) without canWrite/reserved-topic checks used for normal PUBLISH.
(Medium) Cross-session durable corruption. H2PersistentQueue opens queue_"+clientId and queue_"+clientId+"_meta; client id sensor_meta collides with victim sensor metadata map -> corrupts head/tail.
(Medium) Fail-open if authenticator/authorizator class fails to load -> PermitAll/AcceptAll (Server.java:483-531).

Proof of concept

Source-only, no network; PoCs run on JDK 17:

PoCPatternAcl — clientId + gains cross-tenant read/write; clientId # triggers NPE
PoCSharedSubCrash — extractShareName("$share/grp") throws StringIndexOutOfBoundsException
PoCMapCollision — H2 MVStore collision overwrites victim metadata pointer

Impact

Cross-tenant eavesdropping and injection, whole-broker DoS, unauthorized Will publishes, and cross-session durable corruption.

Remediation

Reject clientId/username containing +/# (and / if structural) at CONNECT; expand %c/%u as literal tokens.
Harden SessionEventLoop (catch Throwable + restart supervision) and validate $share filters.
Apply authorization to Will publishes like normal PUBLISH.
Add resource caps (connections, queues, retained, aliases, interceptor queue) + bounded session expiry.
Separate H2 namespaces and fail closed on auth-class load failure.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`io.moquette:moquette-broker`	all versions	0.18.1`io.moquette:moquette-broker:0.18.1`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.moquette:moquette-broker, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update io.moquette:moquette-broker to 0.18.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-95842 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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-95842 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-95842. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

moquette is reachable by untrusted MQTT clients (anonymous by default), so every byte from any client, including pre-authentication, is untrusted. This is a memory-safe JVM: the ceiling is authorization/ACL bypass + denial of service + cross-session integrity, **not RCE** (I did not find one and do not claim one). Audited at commit `da7f719a6bab9829d520b5838e13ea7b1f9be3ef`, module `broker/`. ## What a connecting client can do 1. (Critical) Bypass `pattern`-based ACLs across tenants. In `AuthorizationsCollector.canDoOperation` (AuthorizationsCollector.java:116-131, esp. line 123) the clientI

O3 Security · Impact-Aware SCA

Is CVE-2026-95842 in your dependencies?

O3 Security finds CVE-2026-95842 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works