Mercurial prior to version 4.3 is vulnerable to a missing symlink check that can malicious repositories to modify files outside the repository
www.debian.org/security/2017/dsa-3963
access.redhat.com/errata/RHSA-2017:2489
github.com/advisories/GHSA-hvr9-wr9p-grgr
nvd.nist.gov/vuln/detail/CVE-2017-1000115
security.gentoo.org/glsa/201709-18
web.archive.org/web/20200227155758/www.securityfocus.com/bid/100290
www.mercurial-scm.org/wiki/WhatsNew#Mercurial_4.3_.2F_4.3.1_.282017-08-10.29