There are many sources of warnings and reports on cyber threats.
Here we list a few sources.
To use the RSS feeds, you need an RSS reader or a suitable mail program (e.g. Thunderbird)
RSS feeds
Heise Security Alerts www.heise.de/security/rss/alert-news-atom.xml
Golem Security messages: rss.golem.de/rss.php / rss.golem.de/rss.php
Brief information from CERT-Bund on security gaps and vulnerabilities in IT systems: www.bsi.bund.de/SiteGlobals/Functions/RSSFeed/RSSNewsfeed/RSSNewsfeed_WID.xml
Security information from the BSI Citizens' CERT: www.bsi.bund.de/SiteGlobals/Functions/RSSFeed/RSSNewsfessBSIFB/RSSNewsfeed_BuergerCERT.xml
Threadpost threatpost.com/feed/
NVD (National Vulnerability Database, NSI, USA): all CVEs from the last eight days: nvd.nist.gov/feeds/xml/cve/misc/nvd-rss.xml
NVD (National Vulnerability Database, NSI, USA): all CVE analyzed in the last eight days: nvd.nist.gov/feeds/xml/cve/misc/nvd-rss-analyzed.xml
Websites
Heise Security Alerts www.heise.de/security/alerts/
Golem Security www.golem.de/specials/security/
BSI CERT federal reports www.cert-bund.de/overview
BSI CERT for citizens security advisories www.bsi-fuer-buerger.de/BSIFB/DE/Service/Buerger-CERT/Sicherheitshinweise/Sicherheitshinweise_node.html
Threatpost: threatpost.com
National Vulnerability Database (NIST, USA): nvd.nist.gov