Debian Security Advisory

DLA-1972-1 mosquitto -- LTS security update

Date Reported:
26 Oct 2019
Affected Packages:
Security database references:
In Mitre's CVE dictionary: CVE-2017-7655, CVE-2018-12550, CVE-2018-12551, CVE-2019-11779.
More information:

Several issues have been found in mosquitto, a MQTT version 3.1/3.1.1 compatible message broker.

  • CVE-2017-7655

    A Null dereference vulnerability in the Mosquitto library could lead to crashes for those applications using the library.

  • CVE-2018-12550

    An ACL file with no statements was treated as having a default allow policy. The new behaviour of an empty ACL file is a default policy of access denied. (this is in compliance with all newer releases)

  • CVE-2018-12551

    Malformed authentication data in the password file could allow clients to circumvent authentication and get access to the broker.

  • CVE-2019-11779

    Fix for processing a crafted SUBSCRIBE packet containing a topic that consists of approximately 65400 or more '/' characters. (setting TOPIC_HIERARCHY_LIMIT to 200)

For Debian 8 Jessie, these problems have been fixed in version 1.3.4-2+deb8u4.

We recommend that you upgrade your mosquitto packages.

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: