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.
http://www.securitytracker.com/id/1042001
https://access.redhat.com/errata/RHBA-2019:0327
https://access.redhat.com/errata/RHSA-2018:3041
https://access.redhat.com/errata/RHSA-2018:3505
https://access.redhat.com/errata/RHSA-2019:1260
https://bugs.python.org/issue32981
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-1061
https://docs.python.org/3.5/whatsnew/changelog.html#python-3-5-6-release-candidate-1
https://docs.python.org/3.6/whatsnew/changelog.html#python-3-6-5-release-candidate-1
https://lists.debian.org/debian-lts-announce/2018/09/msg00030.html
https://lists.debian.org/debian-lts-announce/2018/09/msg00031.html
https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbst03951en_us
https://usn.ubuntu.com/3817-1/
https://usn.ubuntu.com/3817-2/
Source: MITRE
Published: 2018-06-19
Updated: 2019-10-03
Type: NVD-CWE-noinfo
Base Score: 5
Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P
Impact Score: 2.9
Exploitability Score: 10
Severity: MEDIUM
Base Score: 7.5
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Impact Score: 3.6
Exploitability Score: 3.9
Severity: HIGH