Provide references for CVE-2021-21401.
Where can I find more information about CVE-2021-21401?
References are available at: https://github.com/nanopb/nanopb/security/advisories/GHSA-7mv5-5mxh-qg88, https://github.com/nanopb/nanopb/issues/647, https://github.com/nanopb/nanopb/commit/e2f0ccf939d9f82931d085acb6df8e9a182a4261, https://github.com/nanopb/nanopb/blob/c9124132a604047d0ef97a09c0e99cd9bed2c818/CHANGELOG.txt#L1.