A flaw was found in spice-server. Multiple migration data handlers use client-supplied offsets from SPICEMSGCMIGRATEDATA messages without bounds validation, allowing a malicious authenticated SPICE client during VM live migration to read arbitrary heap memory or trigger heap corruption via out-of-bounds read and write operations on the message buffer.

A flaw was found in spice-server. The GLZ encoder dictionary restore path truncates a sizet allocation size to int when calling the malloc callback, allowing a malicious authenticated SPICE client during VM live migration to trigger a massive heap buffer overflow by sending a crafted maxencoders value in migration data.