The updated packages fix several bugs and some security issues:
Sandbox escape through Firefox Sync. (CVE-2019-9812)
Memory safety bugs fixed in Firefox 69, Firefox ESR 68.1, and Firefox ESR 60.9. (CVE-2019-11740)
Same-origin policy violation with SVG filters and canvas to steal cross-origin images. (CVE-2019-11742)
Cross-origin access to unload event attributes. (CVE-2019-11743)
XSS by breaking out of title and textarea elements using innerHTML. (CVE-2019-11744)
Use-after-free while manipulating video. (CVE-2019-11746)
Use-after-free while extracting a key value in IndexedDB. (CVE-2019-11752)
Privilege escalation with Mozilla Maintenance Service in custom Firefox installation location. (CVE-2019-11753)