CVE-2021-4206

Name	CVE-2021-4206
Description	A flaw was found in the QXL display device emulation in QEMU. An integer overflow in the cursor_alloc() function can lead to the allocation of a small cursor object followed by a subsequent heap-based buffer overflow. This flaw allows a malicious privileged guest user 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=2036998
https://starlabs.sg/advisories/21/21-4206/
Fixed by: https://gitlab.com/qemu-project/qemu/-/commit/fa892e9abb728e76afcf27323ab29c57fb0fe7aa (v7.0.0-rc4)