Debian: DSA-4559-1 Critical: ProFTPD Denial Of Service Issue

Stephan Zeisberg discovered that missing input validation in ProFTPD, a
FTP/SFTP/FTPS server, could result in denial of service via an infinite
loop.

For the oldstable distribution (stretch), this problem has been fixed
in version 1.3.5b-4+deb9u2.

For the stable distribution (buster), this problem has been fixed in
version 1.3.6-4+deb10u2.

We recommend that you upgrade your proftpd-dfsg packages.

For the detailed security status of proftpd-dfsg please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/source-package/proftpd-dfsg

Further information about Debian Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://www.debian.org/security/