Versions mentioned in the description apply to the upstream
Remediation section below for
Debian:9 relevant versions.
Mercurial before 1.0.2 does not enforce the allowpull permission setting for a pull operation from hgweb, which allows remote attackers to read arbitrary files from a repository via an "hg pull" request.
mercurial to version 1.0.1-5.1 or higher.