PCRE before 8.38 mishandles the interaction of lookbehind assertions and mutually recursive subpatterns, which allows remote attackers to cause a denial of service (buffer overflow) or possibly have unspecified other impact via a crafted regular expression, as demonstrated by a JavaScript RegExp object encountered by Konqueror.

PCRE before 8.38 mishandles certain repeated conditional groups, which allows remote attackers to cause a denial of service (buffer overflow) or possibly have unspecified other impact via a crafted regular expression, as demonstrated by a JavaScript RegExp object encountered by Konqueror.