For Debian 9 stretch, this problem has been fixed in version
1.2.3+dfsg.1-4+deb9u8.
We recommend that you upgrade your roundcube packages.
For the detailed security status of roundcube please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/source-package/roundcube
Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS
Get the latest Linux and open source security news straight to your inbox.