CVE-2021-3592

NameCVE-2021-3592
DescriptionAn invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw exists in the bootp_input() function and could occur while processing a udp packet that is smaller than the size of the 'bootp_t' structure. A malicious guest could use this flaw to leak 10 bytes of uninitialized heap memory from the host. The highest threat from this vulnerability is to data confidentiality. This flaw affects libslirp versions prior to 4.6.0.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-3362-1
Debian Bugs989993

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
libslirp (PTS)bullseye4.4.0-1+deb11u2fixed
bookworm4.7.0-1fixed
sid, trixie4.8.0-1fixed
qemu (PTS)jessie, jessie (lts)1:2.1+dfsg-12+deb8u23vulnerable
stretch (security)1:2.8+dfsg-6+deb9u17vulnerable
stretch (lts), stretch1:2.8+dfsg-6+deb9u19vulnerable
buster (security), buster, buster (lts)1:3.1+dfsg-8+deb10u12fixed
bullseye1:5.2+dfsg-11+deb11u3fixed
bullseye (security)1:5.2+dfsg-11+deb11u2fixed
bookworm1:7.2+dfsg-7+deb12u7fixed
sid, trixie1:9.2.0+ds-2fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
libslirpsourcebullseye4.4.0-1+deb11u2
libslirpsource(unstable)4.6.1-1989993
qemusourcebuster1:3.1+dfsg-8+deb10u10DLA-3362-1
qemusource(unstable)1:4.1-2

Notes

[stretch] - qemu <ignored> (Introduces a regression. See Debian bug #994080. Reverted in DLA-2753-2)
https://gitlab.freedesktop.org/slirp/libslirp/-/commit/93e645e72a056ec0b2c16e0299fc5c6b94e4ca17 (v4.6.0)
https://gitlab.freedesktop.org/slirp/libslirp/-/commit/f13cad45b25d92760bb0ad67bec0300a4d7d5275 (v4.6.0)
https://gitlab.freedesktop.org/slirp/libslirp/-/commit/2eca0838eee1da96204545e22cdaed860d9d7c6c (v4.6.0)
Regression fix: https://gitlab.freedesktop.org/slirp/libslirp/-/commit/c9f314f6e315a5518432761fea864196a290f799 (v4.6.1)
qemu 1:4.1-2 switched to system libslirp, marking that version as fixed.
The patch introduced a regression, see Debian bug #994080 for more information.
[jessie] - qemu <postponed> (Introduces a regression. See Debian bug #994080. Reverted in ELA-481-2)

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