Preface: Microsoft Edge no longer uses Chakra. Microsoft will continue to provide security updates for Chakracore 1.11 until 9th March 2021 but do not intend to support it after that.
Vulnerability details: Microsoft did not describe too much details. However the design weakness of ChakraCore not only discover this time. For the rest of the details, please refer of the attached diagram.
Official announcement – https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2020-17131