CVE-2022-26363

x86 pv: Insufficient care with non-coherent mappings T[his CNA information
record relates to multiple CVEs; the text explains which
aspects/vulnerabilities correspond to which CVE.] Xen maintains a type
reference count for pages, in addition to a regular reference count. This
scheme is used to maintain invariants required for Xen’s safety, e.g. PV
guests may not have direct writeable access to pagetables; updates need
auditing by Xen. Unfortunately, Xen’s safety logic doesn’t account for
CPU-induced cache non-coherency; cases where the CPU can cause the content
of the cache to be different to the content in main memory. In such cases,
Xen’s safety logic can incorrectly conclude that the contents of a page is
safe.

Notes