PCRE before 8.38 mishandles the /(?:|a|){100}x/ pattern and related patterns, which allows remote attackers to cause a denial of service (infinite recursion) or possibly have unspecified other impact via a crafted regular expression, as demonstrated by a JavaScript RegExp object encountered by Konqueror.
Exploitability
AV:NAC:LPR:NUI:NScope
S:UImpact
C:HI:HA:H9.8/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H