Brian Carpenter reported that a crafted regular expression could cause a heap buffer write overflow, with control over the bytes written (CVE-2018-6797).
Nguyen Duc Manh reported that matching a crafted locale dependent regular expression can cause a heap-based buffer over-read and potentially information disclosure (CVE-2018-6798).
GwanYeong Kim reported that 'pack()' could cause a heap buffer write overflow with a large item count (CVE-2018-6913).