Arch Linux Security Advisory ASA-201708-7
========================================
Severity: Critical
Date    : 2017-08-12
CVE-ID  : CVE-2017-1000115 CVE-2017-1000116
Package : mercurial
Type    : multiple issues
Remote  : Yes
Link    : https://security.archlinux.org/AVG-378

Summary
======
The package mercurial before version 4.2.3-1 is vulnerable to multiple
issues including arbitrary command execution and arbitrary filesystem
access.

Resolution
=========
Upgrade to 4.2.3-1.

# pacman -Syu "mercurial>=4.2.3-1"

The problems have been fixed upstream in version 4.2.3.

Workaround
=========
None.

Description
==========
- CVE-2017-1000115 (arbitrary filesystem access)

Mercurial's symlink auditing was incomplete prior to 4.3, and could be
abused to write to files outside the repository.

- CVE-2017-1000116 (arbitrary command execution)

Mercurial < 4.3 was not sanitizing hostnames passed to ssh, allowing
shell injection attacks on clients by specifying a hostname starting
with -oProxyCommand. This is also present in Git (CVE-2017-1000117) and
Subversion (CVE-2017-9800), so please patch those tools as well if you
have them installed.

Impact
=====
A remote attacker can execute arbitrary command on the affected host by
tricking a user into executing a hg command. A remote attacker can use
crafted commits mixing symlinks and regular files to get access to
files outside the repository.

References
=========
https://wiki.mercurial-scm.org/WhatsNew
https://security.archlinux.org/CVE-2017-1000115
https://security.archlinux.org/CVE-2017-1000116