It was discovered that ZeroMQ, a lightweight messaging kernel library
does not properly handle connecting peers before a handshake is
completed. A remote, unauthenticated client connecting to an application
using the libzmq library, running with a socket listening with CURVE encryption/authentication enabled can take advantage of this flaw to
cause a denial of service affecting authenticated and encrypted clients.
For the stable distribution (buster), this problem has been fixed in
We recommend that you upgrade your zeromq3 packages.