CVE-2021-3929

Name	CVE-2021-3929
Description	A DMA reentrancy issue was found in the NVM Express Controller (NVME) emulation in QEMU. This CVE is similar to CVE-2021-3750 and, just like it, when the reentrancy write triggers the reset function nvme_ctrl_reset(), data structs will be freed leading to a use-after-free issue. A malicious guest could use this flaw to crash the QEMU process on the host, resulting in a denial of service condition or, potentially, executing arbitrary code within the context of the QEMU process on the host.
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.

Source Package	Release	Version	Status
qemu (PTS)	bullseye	1:5.2+dfsg-11+deb11u3	vulnerable
	bullseye (security)	1:5.2+dfsg-11+deb11u4	vulnerable
	bookworm	1:7.2+dfsg-7+deb12u13	fixed
	trixie, sid	1:10.0.2+ds-1	fixed

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

Package	Type	Release	Fixed Version
qemu	source	stretch	(not affected)
qemu	source	buster	(not affected)
qemu	source	(unstable)	1:7.0+dfsg-1

Notes

[bullseye] - qemu <ignored> (Minor issue; nvme support preliminary supported)
[buster] - qemu <not-affected> (nvme support preliminary supported; PoC doesn't trigger)
[stretch] - qemu <not-affected> (Vulnerable code introduced later)
https://bugzilla.redhat.com/show_bug.cgi?id=2020298
https://gitlab.com/qemu-project/qemu/-/issues/556 (generic)
https://gitlab.com/qemu-project/qemu/-/issues/782 (specific)
Proposed patchset (generic): https://lists.nongnu.org/archive/html/qemu-devel/2021-08/msg03692.html
Proposed patchset (specific): https://lists.nongnu.org/archive/html/qemu-devel/2022-01/msg04577.html
Fixed by: https://gitlab.com/qemu-project/qemu/-/commit/736b01642d85be832385063f278fe7cd4ffb5221 (v7.0.0-rc0)