python before versions 2.7.15, 3.4.9, 3.5.6rc1, 3.6.5rc1 and 3.7.0 is vulnerable to catastrophic backtracking in the difflib.IS_LINE_JUNK method. An attacker could use this flaw to cause denial of service.
Exploitability
AV:NAC:LPR:NUI:RScope
S:UImpact
C:NI:NA:H6.5/CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:HInput Validation