|Description||A PV guest could DoS Xen while unmapping a grant To address XSA-380, reference counting was introduced for grant mappings for the case where a PV guest would have the IOMMU enabled. PV guests can request two forms of mappings. When both are in use for any individual mapping, unmapping of such a mapping can be requested in two steps. The reference count for such a mapping would then mistakenly be decremented twice. Underflow of the counters gets detected, resulting in the triggering of a hypervisor bug check.|
|Source||CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)|
Vulnerable and fixed packages
The table below lists information on source packages.
|xen (PTS)||buster, buster (security)||4.11.4+107-gef32c7afa2-1||vulnerable|
|bullseye (security), bullseye||4.14.5+94-ge49571868d-1||fixed|
The information below is based on the following data on fixed versions.
|Package||Type||Release||Fixed Version||Urgency||Origin||Debian Bugs|
[buster] - xen <end-of-life> (DSA 4677-1)
[stretch] - xen <end-of-life> (DSA 4602-1)