CVE-2021-28702

Name	CVE-2021-28702
Description	PCI devices with RMRRs not deassigned correctly Certain PCI devices in a system might be assigned Reserved Memory Regions (specified via Reserved Memory Region Reporting, "RMRR"). These are typically used for platform tasks such as legacy USB emulation. If such a device is passed through to a guest, then on guest shutdown the device is not properly deassigned. The IOMMU configuration for these devices which are not properly deassigned ends up pointing to a freed data structure, including the IO Pagetables. Subsequent DMA or interrupts from the device will have unpredictable behaviour, ranging from IOMMU faults to memory corruption.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DSA-5017-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
xen (PTS)	jessie, jessie (lts)	4.4.4lts5-0+deb8u1	vulnerable
	stretch (security), stretch (lts), stretch	4.8.5.final+shim4.10.4-1+deb9u12	fixed
	buster (security), buster, buster (lts)	4.11.4+107-gef32c7afa2-1	fixed
	bullseye	4.14.6-1	fixed
	bullseye (security)	4.14.5+94-ge49571868d-1	fixed
	bookworm	4.17.3+10-g091466ba55-1~deb12u1	fixed
	sid, trixie	4.17.3+36-g54dacb5c02-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin
xen	source	jessie	(unfixed)	end-of-life
xen	source	stretch	(not affected)
xen	source	buster	(not affected)
xen	source	bullseye	4.14.3+32-g9de3671772-1~deb11u1		DSA-5017-1
xen	source	(unstable)	4.14.3+32-g9de3671772-1

Notes

[buster] - xen <not-affected> (Vulnerable code introduced later)
[stretch] - xen <not-affected> (Vulnerable code introduced later)
https://xenbits.xen.org/xsa/advisory-386.html