A use-after-free error can occur when manipulating ranges in selections with one node inside a native anonymous tree and one node outside of it. This results in a potentially exploitable crash. This vulnerability affects Firefox < 52, Firefox ESR < 45.8, Thunderbird < 52, and Thunderbird < 45.8.
http://rhn.redhat.com/errata/RHSA-2017-0459.html
http://rhn.redhat.com/errata/RHSA-2017-0461.html
http://rhn.redhat.com/errata/RHSA-2017-0498.html
https://bugzilla.mozilla.org/show_bug.cgi?id=1340138
https://security.gentoo.org/glsa/201705-06
https://security.gentoo.org/glsa/201705-07
https://www.debian.org/security/2017/dsa-3805
https://www.debian.org/security/2017/dsa-3832
https://www.exploit-db.com/exploits/41660/
https://www.mozilla.org/security/advisories/mfsa2017-05/
https://www.mozilla.org/security/advisories/mfsa2017-06/
https://www.mozilla.org/security/advisories/mfsa2017-07/