Subject: [ASA-202005-6] qemu: multiple issues

Arch Linux Security Advisory ASA-202005-6
=========================================

Severity: High
Date    : 2020-05-07
CVE-ID  : CVE-2019-20382 CVE-2020-1711 CVE-2020-7039
Package : qemu
Type    : multiple issues
Remote  : Yes
Link    : https://security.archlinux.org/AVG-1110

Summary
=======

The package qemu before version 5.0.0-1 is vulnerable to multiple
issues including arbitrary code execution and denial of service.

Resolution
==========

Upgrade to 5.0.0-1.

# pacman -Syu "qemu>=5.0.0-1"

The problems have been fixed upstream in version 5.0.0.

Workaround
==========

None.

Description
===========

- CVE-2019-20382 (denial of service)

A memory leak has been found in in the way VNC display driver of QEMU
<= 4.2.0 handled connection disconnect, when ZRLE, Tight encoding is
enabled. It creates two vncState objects, one of which allocates memory
for Zlib's data object. This allocated memory is not free'd upon
disconnection resulting in the said memory leakage issue.
A user able to connect to the VNC server could use this flaw to leak
host memory leading to a potential DoS scenario.

- CVE-2020-1711 (arbitrary code execution)

An out-of-bounds heap buffer access flaw was found in the way the iSCSI
Block driver in QEMU handled a response coming from an iSCSI server
while checking the status of a Logical Address Block (LBA) in an
iscsi_co_block_status() routine. A remote user could use this flaw to
crash the QEMU process, resulting in a denial of service or potential
execution of arbitrary code with privileges of the QEMU process on the
host.

- CVE-2020-7039 (arbitrary code execution)

A heap buffer overflow issue was found in the SLiRP networking
implementation of the QEMU emulator. This flaw occurs in the tcp_emu()
routine while emulating IRC and other protocols. An attacker could use
this flaw to crash the QEMU process on the host, resulting in a denial
of service or potential execution of arbitrary code with privileges of
the QEMU process.

Impact
======

A remote attacker can crash the QEMU process, and potentially execute
arbitrary code on the host.

References
==========

https://www.openwall.com/lists/oss-security/2020/03/05/1
https://git.qemu.org/?p=qemu.git;a=commitdiff;h=6bf21f3d83e95bcc4ba35a7a07cc6655e8b010b0
https://www.openwall.com/lists/oss-security/2020/01/23/3
https://www.openwall.com/lists/oss-security/2020/01/16/2
https://security.archlinux.org/CVE-2019-20382
https://security.archlinux.org/CVE-2020-1711
https://security.archlinux.org/CVE-2020-7039