In Apache httpd 2.4.0 to 2.4.29, the expression specified in <FilesMatch> could match '$' to a newline character in a malicious filename, rather than matching only the end of the filename. This could be exploited in environments where uploads of some files are are externally blocked, but only by matching the trailing portion of the filename.
https://www.tenable.com/security/tns-2019-09
https://www.debian.org/security/2018/dsa-4164
https://usn.ubuntu.com/3627-2/
https://usn.ubuntu.com/3627-1/
https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03909en_us
https://security.netapp.com/advisory/ntap-20180601-0004/
https://httpd.apache.org/security/vulnerabilities_24.html
https://access.redhat.com/errata/RHSA-2019:0367
https://access.redhat.com/errata/RHSA-2019:0366
https://access.redhat.com/errata/RHSA-2018:3558
http://www.securitytracker.com/id/1040570