[Suggested description]
An issue was discovered in Contiki-NG tinyDTLS through 2018-08-30. A buffer over-read exists in the dtls_sha256_update function. This bug allows remote attackers to cause a denial of service (crash) and possibly read sensitive information by sending a malformed packet with an over-large fragment length field, due to servers incorrectly handling malformed packets.

[Vulnerability Type]
Buffer Overflow

[Vendor of Product]
https://github.com/contiki-ng/tinydtls

[Affected Product Code Base]
contiki-ng tinydtls - master branch 53a0d97

[Affected Component]
the service of dtls servers

[Attack Type]
Remote

[Impact Code execution]
true

[Impact Denial of Service]
true

[Reference]
https://github.com/contiki-ng/tinydtls/issues/21

[Discoverer]
jerrytesting

[CVE Reference]
The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CVE-2021-42147 to this vulnerability.