CVE-2020-12886: arm mbed_os Out-of-bounds Read

Vulnerability summary

CVE-2020-12886 is a critical (CVSS 9.1) Out-of-bounds Read vulnerability in arm mbed_os. EPSS estimates a 1.35% chance of exploitation in the next 30 days, higher than 71.1% of scored vulnerabilities.

Timeline

1. 18-06-2020
   PublishedVulnerability first disclosed.
2. 04-08-2024
   Last modifiedVulnerability information updated.

Description

A buffer over-read was discovered in the CoAP library in Arm Mbed OS 5.15.3. The CoAP parser is responsible for parsing received CoAP packets. The function sn_coap_parser_options_parse() parses the CoAP packet header starting from the message token. The length of the token in the received message is provided in the first byte parsed by the sn_coap_parser_options_parse() function. The length encoded in the message is not validated against the actual input buffer length before accessing the token. As a result, memory access outside of the intended boundary of the buffer may occur.

• CWE-125Out-of-bounds ReadThe product reads data past the end, or before the beginning, of the intended buffer.