Debian Linux Security Advisory 5184-1 - Multiple vulnerabilities have been discovered in the Xen hypervisor, which could result in privilege escalation. In addition this updates provides mitigations for the "Retbleed" speculative execution attack and the "MMIO stale data" vulnerabilities.
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Xen's _get_page_type() contains an ABAC cmpxchg() race, where the code incorrectly assumes that if it reads a specific type_info value, and then later cmpxchg() succeeds, the type_info can't have changed in between.
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