Hello everybody, Don't ignore this email! Last week a critical security bug was reported on our bug tracker. We fixed it and built debian packages for the four stable releases we currently support. The security flaw can cause a privilege escalation from OPAC users. It can be highly damaging, especially if your staff interface is accessible via login from everywhere without further security measures like IP restrictions in place. How to fix the problem? If you are using a debian-based system you should upgrade using the debian packages: % apt update % apt install koha-common If you are using an older version of Koha (<19.11) you should either upgrade to a newer version, or apply those two patches (they should apply on older versions as well): https://paste.debian.net/hidden/885fb5ec/ https://paste.debian.net/hidden/1184f523/ https://paste.debian.net/plainh/ae9f9f25 You can apply them using the following command: % wget "https://paste.debian.net/plainh/885fb5ec" -O 28929_1.patch % wget "https://paste.debian.net/plainh/1184f523" -O 28929_2.patch % wget "https://paste.debian.net/plainh/ae9f9f25" -O 28947.patch % patch -p1 -d /usr/share/koha/intranet/cgi-bin/ < /kohadevbox/koha/28929_1.patch % patch -p1 -d /usr/share/koha/opac/cgi-bin/ < /kohadevbox/koha/28929_2.patch % patch -d /usr/share/koha/opac/cgi-bin/opac/ < /kohadevbox/koha/28947.patch The two bugs are 28929 and 28947. As they contain information about how to recreate the vulnerability they will stay hidden two more days to let you upgrade your systems. Let us know if you have any questions! Regards, Jonathan