Out-of-bounds Read in Arm Mbed OS
CVE-2020-12884
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_multiple_options() parses CoAP options that may occur multiple consecutive times in a single packet. While processing the options, packet_data_pptr is accessed after being incremented by option_len without a prior out-of-bounds memory check. The temp_parsed_uri_query_ptr is validated for a correct range, but the range valid for temp_parsed_uri_query_ptr is derived from the amount of allocated heap memory, not the actual input size. Therefore the check of temp_parsed_uri_query_ptr may be insufficient for safe access to the area pointed to by packet_data_pptr. As a result, access to a memory area outside of the intended boundary of the packet buffer is made.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H.
EPSS exploit prediction
EPSS: 0.014 (70.4th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 70th percentile — 70.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.014 · newest: 0.014 · change: 0.000
Affected products
- Arm Mbed OS — versions 5.15.3
Weakness classification (CWE)
References
- github.com/ARMmbed/mbed-os/issues/12928 (Third Party Advisory)
- github.com/ARMmbed/mbed-coap/pull/116 (Third Party Advisory)
Frequently asked questions
- What is CVE-2020-12884?
- CVE-2020-12884 is a critical-severity vulnerability in Arm Mbed OS, classified under Out-of-bounds Read. CVSS score: 9.1/10. Published 2020-06-18.
- How severe is CVE-2020-12884?
- Critical severity. CVSS v3 base score is 9.1 out of 10.