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.

• CVE ID
• CVE-2020-12884

• Assigner
• cve@mitre.org

• Vulnerability Status
• Analyzed

• Published Version
• 2020-06-18T19:15:09

• Last Modified Date
• 2020-06-25T14:41:37

• Version
• 2.0

• Vector String
• AV:N/AC:L/Au:N/C:P/I:N/A:P

• Access Vector
• NETWORK

• Access Compatibility
• LOW

• Authentication
• NONE

• Confidentiality Impact
• PARTIAL

• Integrity Impact
• NONE

• Availability Impact
• PARTIAL

• Base Score
• 6.4

• Severity
• MEDIUM

• Exploitability Score
• 10

• Impact Score
• 4.9

• Version
• 3.1

• Vector String
• CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

• Attack Vector
• NETWORK

• Attack Compatibility
• LOW

• Privileges Required
• NONE

• User Interaction
• NONE

• Scope
• UNCHANGED

• Confidentiality Impact
• HIGH

• Availability Impact
• HIGH

• Base Score
• 9.1

• Base Severity
• CRITICAL

• Exploitability Score
• 3.9

• Impact Score
• 5.2