What’s Vulnerable › Vulnerabilities

CVE-2026-95843: Moquette malformed shared subscriptions can crash command processing

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-09-23 · updated 2026-09-25
• Weakness: CWE-20

Description

Moquette is a lightweight Java MQTT broker. Prior to 0.18.1, PostOffice.subscribe parses a shared-subscription filter through SharedSubscriptionUtils.extractShareName before validating the complete $share/{shareName}/{topicFilter} structure. A remote client can send a filter such as $share/grp without a topic-filter portion, causing a StringIndexOutOfBoundsException while calculating the share name. The exception terminates command handling on the shared session event loop and can deny service to other client sessions assigned to that loop. This issue is fixed in version 0.18.1.

Affected products

• moquette-io moquette: before 0.18.1 — fixed in 0.18.1

How to fix

Upgrade to a fixed version: moquette-io moquette 0.18.1. Check the vendor advisory for mitigations.

References

• https://github.com/moquette-io/moquette/commit/affdc71fdba92dc020421678970ae70518fb6da2
• https://github.com/moquette-io/moquette/pull/962
• https://github.com/moquette-io/moquette/releases/tag/v0.18.1
• https://github.com/moquette-io/moquette/security/advisories/GHSA-5f42-97gr-vfhq
• https://github.com/moquette-io/moquette/security/advisories/GHSA-5f42-97gr-vfhq

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