| 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, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) | 
| References | DLA-3099-1, DSA-5133-1 | 
The table below lists information on source packages.
| Source Package | Release | Version | Status | 
|---|---|---|---|
| qemu (PTS) | bullseye | 1:5.2+dfsg-11+deb11u3 | fixed | 
| bullseye (security) | 1:5.2+dfsg-11+deb11u5 | fixed | |
| bookworm | 1:7.2+dfsg-7+deb12u16 | fixed | |
| bookworm (security) | 1:7.2+dfsg-7+deb12u15 | fixed | |
| trixie | 1:10.0.3+ds-0+deb13u1 | fixed | |
| trixie (security) | 1:10.0.2+ds-2+deb13u1 | fixed | |
| forky, sid | 1:10.1.2+ds-1 | fixed | 
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs | 
|---|---|---|---|---|---|---|
| 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 | 
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)