doc: update security advisory for 1.6.1 release
Update mitigations for security vulnerabilities
for ACRN 1.6.1 release
Security Advisory
#################
+Addressed in ACRN v1.6.1
+************************
+
+We recommend that all developers upgrade to this v1.6.1 release (or later), which
+addresses the following security issue that was discovered in previous releases:
+
+------
+
+- Service VM kernel Crashes When Fuzzing HC_ASSIGN_PCIDEV and HC_DEASSIGN_PCIDEV
+ NULL pointer dereference due to invalid address of PCI device to be assigned or
+ de-assigned may result in kernel crash. The return value of 'pci_find_bus()' shall
+ be validated before using in 'update_assigned_vf_state()'.
+
+ **Affected Release:** v1.6.
+
+
Addressed in ACRN v1.6
**********************
