Vulnerability · Published Sep 23, 2026 · Assigned by GitHub_M

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

High 8.7

In plain English

A high-severity improper input validation in moquette from moquette-io. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)8.7High

Exploit odds (30 days)0.4%top 62.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Maven	io.moquette:moquette-broker	0.18.1	GHSA-5f42-97gr-vfhq

Affected products (as reported)

Vendor	Product	Versions
moquette-io	moquette	< 0.18.1

Weakness: CWE-20 · 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

References

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