Mbed Mqtt
CVE-2019-17210
HIGH
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
1DescriptionNVD
A denial-of-service issue was discovered in the MQTT library in Arm Mbed OS 2017-11-02. The function readMQTTLenString() is called by the function MQTTDeserialize_publish() to get the length and content of the MQTT topic name. In the function readMQTTLenString(), mqttstring->lenstring.len is a part of user input, which can be manipulated. An attacker can simply change it to a larger value to invalidate the if statement so that the statements inside the if statement are skipped, letting the value of mqttstring->lenstring.data default to zero. Later, curn is accessed, which points to mqttstring->lenstring.data. On an Arm Cortex-M chip, the value at address 0x0 is actually the initialization value for the MSP register. It is highly dependent on the actual firmware. Therefore, the behavior of the program is unpredictable from this time on.
AnalysisAI
A denial-of-service issue was discovered in the MQTT library in Arm Mbed OS 2017-11-02. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Technical ContextAI
This vulnerability is classified under CWE-20. A denial-of-service issue was discovered in the MQTT library in Arm Mbed OS 2017-11-02. The function readMQTTLenString() is called by the function MQTTDeserialize_publish() to get the length and content of the MQTT topic name. In the function readMQTTLenString(), mqttstring->lenstring.len is a part of user input, which can be manipulated. An attacker can simply change it to a larger value to invalidate the if statement so that the statements inside the if statement are skipped, letting the value of mqttstring->lenstring.data default to zero. Later, curn is accessed, which points to mqttstring->lenstring.data. On an Arm Cortex-M chip, the value at address 0x0 is actually the initialization value for the MSP register. It is highly dependent on the actual firmware. Therefore, the behavior of the program is unpredictable from this time on. Affected products include: Arm Mbed-Mqtt, Arm Mbed-Os.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.
Same weakness CWE-20 – Improper Input Validation
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External POC / Exploit Code
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