Zenoss Core through 5 Beta 3 does not include the HTTPOnly flag in a Set-Cookie header for the authentication cookie, which makes it easier for remote attackers to obtain credential information via script access to this cookie, aka ZEN-10418.
Zenoss Core through 5 Beta 3 allows remote attackers to obtain sensitive information by attempting a product-rename action with an invalid new name and then reading a stack trace, as demonstrated by internal URL information, aka ZEN-15382.
The XML-RPC subsystem in Zenoss 2.5.3 allows XXE attacks that lead to unauthenticated information disclosure via port 9988.