In affected versions of WordPress, files with a specially crafted name when uploaded to the Media section can lead to script execution upon accessing the file. This requires an authenticated user with privileges to upload files. This has been patched in version 5.4.1, along with all the previously affected versions via a minor release (5.3.3, 5.2.6, 5.1.5, 5.0.9, 4.9.14, 4.8.13, 4.7.17, 4.6.18, 4.5.21, 4.4.22, 4.3.23, 4.2.27, 4.1.30, 4.0.30, 3.9.31, 3.8.33, 3.7.33).
https://www.debian.org/security/2020/dsa-4677
https://wordpress.org/support/wordpress-version/version-5-4-1/#security-updates
https://lists.debian.org/debian-lts-announce/2020/05/msg00011.html
https://github.com/WordPress/wordpress-develop/security/advisories/GHSA-3gw2-4656-pfr2