Mozilla -- multiple vulnerabilities

Mozilla Foundation reports:

CVE-2019-11703: Heap buffer overflow in icalparser.c
A flaw in Thunderbird’s implementation of iCal causes a heap
buffer overflow in parser_get_next_char when processing certain
email messages, resulting in a potentially exploitable crash.
CVE-2019-11704: Heap buffer overflow in icalvalue.c
A flaw in Thunderbird’s implementation of iCal causes a heap
buffer overflow in icalmemory_strdup_and_dequote when processing
certain email messages, resulting in a potentially exploitable
crash.
CVE-2019-11705: Stack buffer overflow in icalrecur.c
A flaw in Thunderbird’s implementation of iCal causes a stack
buffer overflow in icalrecur_add_bydayrules when processing
certain email messages, resulting in a potentially exploitable
crash.
CVE-2019-11706: Type confusion in icalproperty.c
A flaw in Thunderbird’s implementation of iCal causes a type
confusion in icaltimezone_get_vtimezone_properties when
processing certain email messages, resulting in a crash.