Auth bypass in Moquette
CVE-2026-85724
Moquette is a lightweight Java MQTT broker. Prior to 0.18.1, when pattern-based ACL rules are configured, AuthorizationsCollector.canDoOperation substitutes client ID and username values directly into rules containing %c or %u and then treats the result as an MQTT topic filter. A client that uses + or # in either identity can broaden the substituted filter and gain cross-tenant read and write access. A # identity can also produce an invalid filter that triggers a NullPointerException in Topic.match and disrupts session processing. This issue is fixed in version 0.18.1.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.6 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.003 (24.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 24.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000
Affected products
- Moquette
- Moquette-Io Moquette — versions < 0.18.1
Weakness classification (CWE)
References
- github.com/moquette-io/moquette/security/advisories/GHSA-5f42-97gr-vfhq (Exploit, Mitigation, Vendor Advisory)
- github.com/moquette-io/moquette/commit/b4a98bb3f3425ece476ed073aa080c627c1239af (Patch)
- github.com/moquette-io/moquette/releases/tag/v0.18.1 (Release Notes)
Frequently asked questions
- What is CVE-2026-85724?
- CVE-2026-85724 is a critical-severity vulnerability in Moquette, classified under CWE-155. CVSS score: 9.6/10. Published 2026-09-23.
- How severe is CVE-2026-85724?
- Critical severity. CVSS v3 base score is 9.6 out of 10.