View at Official ubuntu advisory, NVD, CVE.org · CVE detail
Freshness: upstream tracker timestamp is available; use API updated time as primary recency signal.
CVE-2017-17458 medium priority: Ubuntu including 1 source packages (mercurial), 7 status rows across 7 suites (artful, bionic, cosmic, trusty, upstream, xenial, zesty): released 3, ignored 2, not-affected 2.
In Mercurial before 4.4.1, it is possible that a specially malformed repository can cause Git subrepositories to run arbitrary code in the form of a .git/hooks/post-update script checked into the repository. Typical use of Mercurial prevents construction of such repositories, but they can be created programmatically.