Unconditionally do TLB flushing ahead of page scrubbing
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 4.3epss 0.2%
exploitation probability
0.2%top 86% of all CVEs
observed exploitation
nono source reports it
x86 PV guests can free memory pages while still keeping a stale TLB entry
pointing to them. A TLB flush is only issued by Xen (if needed) when the
page is re-used. Since it's possible for the page to be scrubbed ahead of
the TLB flush, there's a window where a PV guest can modify an already
scrubbed page.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Affected products
Xen · Xen