ELA-481-1 qemu security update

denial-of-service

2021-08-31
Packageqemu
Version1:2.1+dfsg-12+deb8u21
Related CVEs CVE-2021-3527 CVE-2021-3592 CVE-2021-3594 CVE-2021-3682 CVE-2021-3713

Several security vulnerabilities have been found in Qemu, a fast processor emulator.

CVE-2021-3713

An out-of-bounds write flaw was found in the UAS (USB Attached SCSI) device
emulation of QEMU. The device uses the guest supplied stream number
unchecked, which can lead to out-of-bounds access to the UASDevice->data3
and UASDevice->status3 fields. A malicious guest user could use this flaw
to crash QEMU or potentially achieve code execution with the privileges of
the QEMU process on the host.

CVE-2021-3682

A flaw was found in the USB redirector device emulation of QEMU. It occurs
when dropping packets during a bulk transfer from a SPICE client due to the
packet queue being full. A malicious SPICE client could use this flaw to
make QEMU call free() with faked heap chunk metadata, resulting in a crash
of QEMU or potential code execution with the privileges of the QEMU process
on the host.

CVE-2021-3527

A flaw was found in the USB redirector device (usb-redir) of QEMU. Small
USB packets are combined into a single, large transfer request, to reduce
the overhead and improve performance. The combined size of the bulk
transfer is used to dynamically allocate a variable length array (VLA) on
the stack without proper validation. Since the total size is not bounded, a
malicious guest could use this flaw to influence the array length and cause
the QEMU process to perform an excessive allocation on the stack, resulting
in a denial of service.

CVE-2021-3594

An invalid pointer initialization issue was found in the SLiRP networking
implementation of QEMU. The flaw exists in the udp_input() function and
could occur while processing a udp packet that is smaller than the size of
the 'udphdr' structure. This issue may lead to out-of-bounds read access or
indirect host memory disclosure to the guest. The highest threat from this
vulnerability is to data confidentiality.

CVE-2021-3592

An 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.

For Debian 8 jessie, these problems have been fixed in version 1:2.1+dfsg-12+deb8u21.

We recommend that you upgrade your qemu packages.

Further information about Extended LTS security advisories can be found at: https://deb.freexian.com/extended-lts/