A use-after-free vulnerability can occur in HTTP/2 when a cached HTTP/2 stream is closed while still in use, resulting in a potentially exploitable crash. This vulnerability affects Firefox ESR < 60.8, Firefox < 68, and Thunderbird < 60.8.
https://www.mozilla.org/security/advisories/mfsa2019-23/
https://www.mozilla.org/security/advisories/mfsa2019-22/
https://www.mozilla.org/security/advisories/mfsa2019-21/
https://security.gentoo.org/glsa/201908-20
https://security.gentoo.org/glsa/201908-12
https://lists.debian.org/debian-lts-announce/2019/08/msg00002.html
https://lists.debian.org/debian-lts-announce/2019/08/msg00001.html
https://bugzilla.mozilla.org/show_bug.cgi?id=1528481
http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00010.html
http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00009.html
http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00073.html
http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00058.html
http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00055.html