| Name | CVE-2021-20196 |
| Description | A NULL pointer dereference flaw was found in the floppy disk emulator of QEMU. This issue occurs while processing read/write ioport commands if the selected floppy drive is not initialized with a block device. This flaw allows a privileged guest user to crash the QEMU process on the host, resulting in a denial of service. The highest threat from this vulnerability is to system availability. |
| Source | CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| References | DLA-2970-1, DLA-3099-1 |
| Debian Bugs | 984453 |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| qemu (PTS) | jessie, jessie (lts) | 1:2.1+dfsg-12+deb8u23 | fixed |
| stretch (security) | 1:2.8+dfsg-6+deb9u17 | fixed |
| stretch (lts), stretch | 1:2.8+dfsg-6+deb9u19 | fixed |
| buster | 1:3.1+dfsg-8+deb10u8 | vulnerable |
| buster (security) | 1:3.1+dfsg-8+deb10u12 | fixed |
| bullseye | 1:5.2+dfsg-11+deb11u3 | fixed |
| bullseye (security) | 1:5.2+dfsg-11+deb11u2 | vulnerable |
| bookworm | 1:7.2+dfsg-7+deb12u5 | fixed |
| trixie | 1:8.2.1+ds-2 | fixed |
| sid | 1:8.2.2+ds-2 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|
| qemu | source | jessie | (not affected) | | | |
| qemu | source | stretch | 1:2.8+dfsg-6+deb9u17 | | DLA-2970-1 | |
| qemu | source | buster | 1:3.1+dfsg-8+deb10u9 | | DLA-3099-1 | |
| qemu | source | bullseye | 1:5.2+dfsg-11+deb11u3 | | | |
| qemu | source | (unstable) | 1:6.2+dfsg-1 | | | 984453 |
Notes
https://bugzilla.redhat.com/show_bug.cgi?id=1919210
https://bugs.launchpad.net/qemu/+bug/1912780
https://gitlab.com/qemu-project/qemu/-/issues/338
https://lists.nongnu.org/archive/html/qemu-devel/2021-01/msg05986.html
Fixed by: https://gitlab.com/qemu-project/qemu/-/commit/1ab95af033a419e7a64e2d58e67dd96b20af5233 (v6.2.0-rc4)
[jessie] - qemu <not-affected> (Vulnerable code introduced later)