A flaw was found in the way samba implemented DCE/RPC. If a client to a Samba server sent a very large DCE/RPC request, and chose to fragment it, an attacker could replace later fragments with their own data, bypassing the signature requirements.
https://bugzilla.redhat.com/show_bug.cgi?id=2019666
https://security.gentoo.org/glsa/202309-06