There are many websites and sources you should be familiar with and check on a regular basis. Many of these sites will also have RSS feeds you should subscribe to.
Microsoft
https://msrc.microsoft.com/update-guide
https://www.microsoft.com/en-us/msrc/technical-security-notifications
FSLogix (VDI Hugs) https://docs.microsoft.com/en-us/fslogix/whats-new
Citrix
VMware
https://www.vmware.com/security/advisories.html
Cisco
https://tools.cisco.com/security/center/publicationListing.x
Palo Alto
https://security.paloaltonetworks.com/
F5
https://support.f5.com/csp/new-updated-articles
https://support.f5.com/csp/knowledge-center/security
Dell
https://www.dell.com/support/security/en-us
HP
https://support.hp.com/us-en/security-bulletins
IBM
https://www.ibm.com/blogs/psirt/
Oracle
https://www.oracle.com/security-alerts/
IGEL
https://kb.igel.com/securitysafety/en/igel-product-security-information-10346597.html
Stratodesk