CVE-2020-12883 Detail

Current Description

Buffer over-reads were 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 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 option delta and option length bytes. The actual input packet length is not verified against the number of bytes read when processing the option extended delta and the option extended length. Moreover, the calculation of the message_left variable, in the case of non-extended option deltas, is incorrect and indicates more data left for processing than provided in the function input. All of these lead to heap-based or stack-based memory location read access that is outside of the intended boundary of the buffer. Depending on the platform-specific memory management mechanisms, it can lead to processing of unintended inputs or system memory access violation errors.


View Analysis Description

Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score
NIST: NVD
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


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Note: NVD Analysts have published a CVSS score for this CVE based on publicly available information at the time of analysis. The CNA has not provided a score within the CVE List.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://github.com/ARMmbed/mbed-coap/pull/116 Third Party Advisory 
https://github.com/ARMmbed/mbed-os/issues/12925 Third Party Advisory 
https://github.com/ARMmbed/mbed-os/issues/12926 Third Party Advisory 
https://github.com/ARMmbed/mbed-os/issues/12927 Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer cwe source acceptance level NIST  

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Change History

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Quick Info

CVE Dictionary Entry:
CVE-2020-12883
NVD Published Date:
06/18/2020
NVD Last Modified:
06/25/2020
Source:
MITRE