CVE-2021-4207

Name	CVE-2021-4207
Description	A flaw was found in the QXL display device emulation in QEMU. A double fetch of guest controlled values `cursor->header.width` and `cursor->header.height` can lead to the allocation of a small cursor object followed by a subsequent heap-based buffer overflow. A malicious privileged guest user could use this flaw to crash the QEMU process on the host or potentially execute arbitrary code within the context of the QEMU process.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub advisories/code/issues, web search, more)
References	DLA-3099-1, DSA-5133-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
qemu (PTS)	buster	1:3.1+dfsg-8+deb10u8	vulnerable
	buster (security)	1:3.1+dfsg-8+deb10u10	fixed
	bullseye (security), bullseye	1:5.2+dfsg-11+deb11u2	fixed
	bookworm, sid	1:7.2+dfsg-7	fixed

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

Package	Type	Release	Fixed Version	Origin
qemu	source	buster	1:3.1+dfsg-8+deb10u9	DLA-3099-1
qemu	source	bullseye	1:5.2+dfsg-11+deb11u2	DSA-5133-1
qemu	source	(unstable)	1:7.0+dfsg-1

Notes

https://bugzilla.redhat.com/show_bug.cgi?id=2036966
https://starlabs.sg/advisories/21/21-4207/
Fixed by: https://gitlab.com/qemu-project/qemu/-/commit/9569f5cb5b4bffa9d3ebc8ba7da1e03830a9a895 (v7.0.0-rc4)