CVE-2019-17210
A denial-of-service issue was discovered in the MQTT library in Arm Mbed OS 2017-11-02.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.01%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 1.01% probability · 63th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-20
- Affected
- arm/mbed-mqtt · arm/mbed-os
- Source
- cve@mitre.org
EPSS 1.0% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/ARMmbed/mbed-os/issues/11802Issue Tracking, Third Party Advisory
- https://github.com/ARMmbed/mbed-os/issues/11802Issue Tracking, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.