A vulnerability was found in the way Mercurial handles path auditing and caches the results. An attacker could abuse a repository with a series of commits mixing symlinks and regular files/directories to trick Mercurial into writing outside of a given repository.
The symlink auditor is sometimes cached too long, and can be confused into allowing write access to outside the repo.
Name: the Mercurial Security Team
Created mercurial tracking bugs for this issue:
Affects: fedora-all [bug 1480454]
This issue has been addressed in the following products:
Red Hat Enterprise Linux 7
Via RHSA-2017:2489 https://access.redhat.com/errata/RHSA-2017:2489