CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:N/AC:L/Au:N/C:C/I:C/A:C
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
AI Score
Confidence
High
EPSS
Percentile
91.4%
Buffer overflows were discovered in the CoAP library in Arm Mbed OS 5.14.0. The CoAP parser is responsible for parsing received CoAP packets. The function sn_coap_parser_options_parse() parses CoAP input linearly using a while loop. Once an option is parsed in a loop, the current point (packet_data_pptr) is increased correspondingly. The pointer is restricted by the size of the received buffer, as well as by the 0xFF delimiter byte. Inside each while loop, the check of the value of packet_data_pptr is not strictly enforced. More specifically, inside a loop, packet_data_pptr could be increased and then dereferenced without checking. Moreover, there are many other functions in the format of sn_coap_parser_*() that do not check whether the pointer is within the bounds of the allocated buffer. All of these lead to heap-based or stack-based buffer overflows, depending on how the CoAP packet buffer is allocated.
github.com/ARMmbed/mbed-os/blob/d91ed5fa42ea0f32e4422a3c562e7b045a17da40/features/frameworks/mbed-coap/source/sn_coap_parser.c#L257
github.com/ARMmbed/mbed-os/blob/d91ed5fa42ea0f32e4422a3c562e7b045a17da40/features/frameworks/mbed-coap/source/sn_coap_parser.c#L301
github.com/ARMmbed/mbed-os/blob/d91ed5fa42ea0f32e4422a3c562e7b045a17da40/features/frameworks/mbed-coap/source/sn_coap_parser.c#L310
github.com/ARMmbed/mbed-os/blob/d91ed5fa42ea0f32e4422a3c562e7b045a17da40/features/frameworks/mbed-coap/source/sn_coap_parser.c#L313
github.com/ARMmbed/mbed-os/blob/d91ed5fa42ea0f32e4422a3c562e7b045a17da40/features/frameworks/mbed-coap/source/sn_coap_parser.c#L331
github.com/ARMmbed/mbed-os/blob/d91ed5fa42ea0f32e4422a3c562e7b045a17da40/features/frameworks/mbed-coap/source/sn_coap_parser.c#L660
github.com/ARMmbed/mbed-os/issues/11803
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:N/AC:L/Au:N/C:C/I:C/A:C
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
AI Score
Confidence
High
EPSS
Percentile
91.4%