An issue was discovered in the Linux kernel through 5.11.6. fastrpc_internal_invoke in drivers/misc/fastrpc.c does not prevent user applications from sending kernel RPC messages, aka CID-20c40794eb85. This is a related issue to CVE-2019-2308.
git.kernel.org/linus/20c40794eb85ea29852d7bc37c55713802a543d6
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OMRQVOTASD3VZP6GE4JJHE27QU6FHTZ6/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TJPVQZPY3DHPV5I3IVNMSMO6D3PKZISX/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XAUNYDTGE6MB4NWL2SIHPCODCLET3JZB/
lore.kernel.org/stable/YD03ew7+6v0XPh6l%40kroah.com/
security.netapp.com/advisory/ntap-20210401-0003/