Toni Huttunen discovered that the Shibboleth service provider’s template engine used to render error pages could be abused for phishing attacks.
For additional information please refer to the upstream advisory at https://shibboleth.net/community/advisories/secadv_20210317.txt
For Debian 8 jessie, these problems have been fixed in version 2.5.3+dfsg-2+deb8u2.
We recommend that you upgrade your shibboleth-sp2 packages.
Further information about Extended LTS security advisories can be found at: https://deb.freexian.com/extended-lts/