In 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 CPU usage, leading to a loss of performance and possible denial of service.

The remote Ubuntu 20.04 ESM / 22.04 LTS / 23.04 host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-6492-1 advisory.

    Kathrin Kleinhammer discovered that Mosquitto incorrectly handled certain inputs. If a user or an     automated system were provided with a specially crafted input, a remote attacker could possibly use this     issue to cause a denial of service. This issue only affected Ubuntu 20.04 LTS. (CVE-2021-34431)

    Zhanxiang Song discovered that Mosquitto incorrectly handled certain inputs. If a user or an automated     system were provided with a specially crafted input, a remote attacker could possibly use this issue to     cause an authorisation bypass. This issue only affected Ubuntu 22.04 LTS and Ubuntu 23.04.
    (CVE-2021-34434)

    Zhanxiang Song, Bin Yuan, DeQing Zou, and Hai Jin discovered that Mosquitto incorrectly handled certain     inputs. If a user or an automated system were provided with a specially crafted input, a remote attacker     could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 20.04 LTS and     Ubuntu 22.04 LTS. (CVE-2021-41039)

    Zhengjie Du discovered that Mosquitto incorrectly handled certain inputs. If a user or an automated system     were provided with a specially crafted input file, a remote attacker could possibly use this issue to     cause a denial of service. (CVE-2023-0809)

    It was discovered that Mosquitto incorrectly handled certain inputs. If a user or an automated system were     provided with a specially crafted input, a remote attacker could possibly use this issue to cause a denial     of service. (CVE-2023-3592)

    Mischa Bachmann discovered that Mosquitto incorrectly handled certain inputs. If a user or an automated     system were provided with a specially crafted input, a remote attacker could possibly use this issue to     cause a denial of service. This issue was only fixed in Ubuntu 22.04 LTS and Ubuntu 23.04.
    (CVE-2023-28366)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Debian 11 / 12 host has packages installed that are affected by multiple vulnerabilities as referenced in the dsa-5511 advisory.

  - In Eclipse Mosquitto versions 2.0 to 2.0.11, when using the dynamic security plugin, if the ability for a     client to make subscriptions on a topic is revoked when a durable client is offline, then existing     subscriptions for that client are not revoked. (CVE-2021-34434)

  - In 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 CPU usage, leading to a loss of performance and possible denial     of service. (CVE-2021-41039)

  - The 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 with duplicate message IDs, and fails to respond to     PUBREC commands. This occurs because of mishandling of EAGAIN from the libc send function.
    (CVE-2023-28366)

  - 2.0.17  Broker:  * Fix `max_queued_messages 0` stopping clients from receiving messages * Fix     `max_inflight_messages` not being set correctly.  Apps:  * Fix `mosquitto_passwd -U` backup file creation.
    2.0.16  Security:  * CVE-2023-28366: Fix memory leak in broker when clients send multiple QoS 2 messages     with the same message ID, but then never respond to the PUBREC commands. * CVE-2023-0809: Fix excessive     memory being allocated based on malicious initial packets that are not CONNECT packets. * CVE-2023-3592:
    Fix memory leak when clients send v5 CONNECT packets with a will message that contains invalid property     types. * Broker will now reject Will messages that attempt to publish to $CONTROL/. * Broker now validates     usernames provided in a TLS certificate or TLS-PSK identity are valid UTF-8. * Fix potential crash when     loading invalid persistence file. * Library will no longer allow single level wildcard certificates, e.g.
    *.com  Broker:  * Fix $SYS messages being expired after 60 seconds and hence unchanged values     disappearing. * Fix some retained topic memory not being cleared immediately after used. * Fix error     handling related to the `bind_interface` option. * Fix std* files not being redirected when daemonising,     when built with assertions removed. * Fix default settings incorrectly allowing TLS v1.1. * Use line     buffered mode for stdout. Closes #2354. * Fix bridges with non-matching cleansession/local_cleansession     being expired on start after restoring from persistence. * Fix connections being limited to 2048 on     Windows. The limit is now 8192, where supported. * Broker will log warnings if sensitive files are world     readable/writable, or if the owner/group is not the same as the user/group the broker is running as. In     future versions the broker will refuse to open these files.  * mosquitto_memcmp_const is now more constant     time. * Only register with DLT if DLT logging is enabled. * Fix any possible case where a json string     might be incorrectly loaded. This could have caused a crash if a textname or textdescription field of a     role was not a string, when loading the dynsec config from file only. * Dynsec plugin will not allow     duplicate clients/groups/roles when loading config from file, which matches the behaviour for when     creating them. * Fix heap overflow when reading corrupt config with log_dest file.  Client library:  *     Use CLOCK_BOOTTIME when available, to keep track of time. This solves the problem of the client OS     sleeping and the client hence not being able to calculate the actual time for keepalive purposes. * Fix     default settings incorrectly allowing TLS v1.1. * Fix high CPU use on slow TLS connect.  Clients:  * Fix     incorrect topic-alias property value in mosquitto_sub json output. * Fix confusing message on TLS     certificate verification.  Apps:  * mosquitto_passwd uses mkstemp() for backup files. * `mosquitto_ctrl     dynsec init` will refuse to overwrite an existing file, without a race-condition.   (CVE-2023-0809,     CVE-2023-3592)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Severity
186038	Ubuntu 20.04 ESM / 22.04 LTS / 23.04 : Mosquitto vulnerabilities (USN-6492-1)	Nessus	Ubuntu Local Security Checks	medium
182418	Debian DSA-5511-1 : mosquitto - security update	Nessus	Debian Local Security Checks	medium

Detections

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CVE-2021-41039

high

Tenable Plugins

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medium