CVE-2019-17211

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.6% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2019-11-05 · updated 2026-06-17
Weakness: CWE-190

Description

An integer overflow was discovered in the CoAP library in Arm Mbed OS 5.14.0. The function sn_coap_builder_calc_needed_packet_data_size_2() is used to calculate the required memory for the CoAP message from the sn_coap_hdr_s data structure. Both returned_byte_count and src_coap_msg_ptr->payload_len are of type uint16_t. When added together, the result returned_byte_count can wrap around the maximum uint16_t value. As a result, insufficient buffer space is allocated for the corresponding CoAP message.

Affected products

Mbed: 5.13.2, 5.14.0

References

https://github.com/ARMmbed/mbed-os/blob/d0686fd30b4d3d02efdc7e4d0fbf0dfe173543b6/features/frameworks/mbed-coap/source/sn_coap_builder.c#L1090
https://github.com/ARMmbed/mbed-os/blob/d0686fd30b4d3d02efdc7e4d0fbf0dfe173543b6/features/frameworks/mbed-coap/source/sn_coap_builder.c#L355
https://github.com/ARMmbed/mbed-os/blob/d0686fd30b4d3d02efdc7e4d0fbf0dfe173543b6/features/frameworks/mbed-coap/source/sn_coap_builder.c#L524
https://github.com/ARMmbed/mbed-os/blob/d0686fd30b4d3d02efdc7e4d0fbf0dfe173543b6/features/frameworks/mbed-coap/source/sn_coap_builder.c#L527
https://github.com/ARMmbed/mbed-os/blob/d0686fd30b4d3d02efdc7e4d0fbf0dfe173543b6/features/frameworks/mbed-coap/source/sn_coap_builder.c#L710
https://github.com/ARMmbed/mbed-os/blob/d0686fd30b4d3d02efdc7e4d0fbf0dfe173543b6/features/frameworks/mbed-coap/source/sn_coap_builder.c#L718
https://github.com/ARMmbed/mbed-os/blob/d0686fd30b4d3d02efdc7e4d0fbf0dfe173543b6/features/frameworks/mbed-coap/source/sn_coap_builder.c#L746
https://github.com/ARMmbed/mbed-os/issues/11804
https://github.com/ARMmbed/mbed-os/blob/d0686fd30b4d3d02efdc7e4d0fbf0dfe173543b6/features/frameworks/mbed-coap/source/sn_coap_builder.c#L1090
https://github.com/ARMmbed/mbed-os/blob/d0686fd30b4d3d02efdc7e4d0fbf0dfe173543b6/features/frameworks/mbed-coap/source/sn_coap_builder.c#L355
https://github.com/ARMmbed/mbed-os/blob/d0686fd30b4d3d02efdc7e4d0fbf0dfe173543b6/features/frameworks/mbed-coap/source/sn_coap_builder.c#L524
https://github.com/ARMmbed/mbed-os/blob/d0686fd30b4d3d02efdc7e4d0fbf0dfe173543b6/features/frameworks/mbed-coap/source/sn_coap_builder.c#L527

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