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Vulnerability record · CVE-2018-12550 · published 27 March 2019

CVE-2018-12550: Eclipse mosquitto vulnerability

Eclipse · Mosquitto

When Eclipse Mosquitto version 1.0 to 1.5.5 (inclusive) is configured to use an ACL file, and that ACL file is empty, or contains only comments or blank lines, then Mosquitto will treat this as though no ACL file has been defined and use a default allow policy. The new behaviour is to have an empty ACL file mean that all access is denied, which is not a useful configuration but is not unexpected.

8.1 CVSS 3.0 High EPSS 1.4% · top 29.5% CWE-440 · CWE-440
8.1CVSS 3.0 base score, v2 6.8
1.4%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References
17 Jun 2026Last modified by NVD

Description

When Eclipse Mosquitto version 1.0 to 1.5.5 (inclusive) is configured to use an ACL file, and that ACL file is empty, or contains only comments or blank lines, then Mosquitto will treat this as though no ACL file has been defined and use a default allow policy. The new behaviour is to have an empty ACL file mean that all access is denied, which is not a useful configuration but is not unexpected.

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://bugs.eclipse.org/bugs/show_bug.cgi?id=541870 Issue TrackingVendor Advisory
https://lists.debian.org/debian-lts-announce/2019/10/msg00035.html
https://bugs.eclipse.org/bugs/show_bug.cgi?id=541870 Issue TrackingVendor Advisory
https://lists.debian.org/debian-lts-announce/2019/10/msg00035.html

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

8.1CVE-2018-12551Eclipse mosquitto improper authentication vulnerabilityWhen Eclipse Mosquitto version 1.0 to 1.5.5 (inclusive) is configured to use a password file for authentication, any malformed data in the password f…EPSS 1.5%7.5CVE-2023-5632Eclipse mosquitto vulnerabilityIn Eclipse Mosquito before and including 2.0.5, establishing a connection to the mosquitto server without sending data causes the EPOLLOUT event to b…EPSS 0.69%7.5CVE-2023-3592Eclipse mosquitto memory leak vulnerabilityIn Mosquitto before 2.0.16, a memory leak occurs when clients send v5 CONNECT packets with a will message that contains invalid property types.EPSS 0.79%7.5CVE-2023-28366Eclipse mosquitto memory leak vulnerabilityThe broker in Eclipse Mosquitto 1.3.2 through 2.x before 2.0.16 has a memory leak that can be abused remotely when a client sends many QoS 2 messages…EPSS 1.3%7.5CVE-2021-41039Eclipse mosquitto vulnerabilityIn versions 1.6 to 2.0.11 of Eclipse Mosquitto, an MQTT v5 client connecting with a large number of user-property properties could cause excessive CP…EPSS 1.4%7.5CVE-2021-34432Eclipse mosquitto improper input validation vulnerabilityIn Eclipse Mosquitto versions 2.0.7 and earlier, the server will crash if the client tries to send a PUBLISH packet with topic length = 0.EPSS 1.2%7.5CVE-2017-7655Eclipse mosquitto null pointer dereference vulnerabilityIn Eclipse Mosquitto version from 1.0 to 1.4.15, a Null Dereference vulnerability was found in the Mosquitto library which could lead to crashes for …EPSS 1.8%7.5CVE-2018-20145Eclipse mosquitto incorrect permission assignment vulnerabilityEclipse Mosquitto 1.5.x before 1.5.5 allows ACL bypass: if the option per_listener_settings was set to true, and the default listener was in use, and…EPSS 1.6%

Source: NIST National Vulnerability Database (record CVE-2018-12550), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.