I found a issue in regex (findall search)function, when seaching some content by some pattern, the function return for a long long time, match performance is very low.
I think this issue could lead to too low query performance, or a attacker may exploit the issue to cause a denail of service condition.


system:  python 2.7.14  regex(2018.2.21)
poc:

import re
pat = r'^(\(?[\w\d\-\.\\]{3,}\|?){1,}[\w\d\-\.\\]{3,}\)?$'
#plaintext content
content = r'(ftp\x3a\x2f\x2f|http\x3a\x2f\x2f|https\x3a\x2f\x2f|c\x3a\x2f\x2f|d\x3a\x2f\x2f|e\x3a\x2f\x2f)a'
result = re.findall(pat, content)
print result