CVE-2021-20196

NameCVE-2021-20196
DescriptionA 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
ReferencesDLA-2970-1
Debian Bugs984453

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
qemu (PTS)stretch1:2.8+dfsg-6+deb9u9vulnerable
stretch (security)1:2.8+dfsg-6+deb9u17fixed
buster, buster (security)1:3.1+dfsg-8+deb10u8vulnerable
bullseye1:5.2+dfsg-11+deb11u1vulnerable
bullseye (security)1:5.2+dfsg-11+deb11u2vulnerable
bookworm, sid1:7.0+dfsg-7fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
qemusourcestretch1:2.8+dfsg-6+deb9u17DLA-2970-1
qemusource(unstable)1:6.2+dfsg-1984453

Notes

[bullseye] - qemu <postponed> (Minor issue, revisit when fixed upstream)
[buster] - qemu <postponed> (Fix along in future DSA)
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)

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