PCRE 7.8 and 8.32 through 8.37, and PCRE2 10.10 mishandle group empty matches, which might allow remote attackers to cause a denial of service (stack-based buffer overflow) via a crafted regular expression, as demonstrated by /^(?:(?(1)\\.|([^\\\\W_])?)+)+$/.

Heap-based buffer overflow in PCRE 8.34 through 8.37 and PCRE2 10.10 allows remote attackers to execute arbitrary code via a crafted regular expression, as demonstrated by /^(?P=B)((?P=B)(?J:(?P<B>c)(?P<B>a(?P=B)))>WGXCREDITS)/, a different vulnerability than CVE-2015-8384.

The compile_branch function in pcre_compile.c in PCRE 8.x before 8.39 and pcre2_compile.c in PCRE2 before 10.22 mishandles patterns containing an (*ACCEPT) substring in conjunction with nested parentheses, which allows remote attackers to execute arbitrary code or cause a denial of service (stack-based buffer overflow) via a crafted regular expression, as demonstrated by a JavaScript RegExp object encountered by Konqueror, aka ZDI-CAN-3542.