Arm Mbed OS 5.14.0 Integer Overflow or Wraparound Vulnerability


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.


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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.


Vulnerable Systems:

Arm Mbed OS 5.14.0


CVE Information:



Disclosure Timeline:
Published Date:11/5/2019