Provide references for CVE-2020-21913.
Where can I find more information about CVE-2020-21913?
References are available at: https://unicode-org.atlassian.net/browse/ICU-20850, https://github.com/unicode-org/icu/pull/886, https://lists.debian.org/debian-lts-announce/2021/10/msg00008.html, https://www.debian.org/security/2021/dsa-5014.