Disclosure summary
Python's elementtree C accelerator failed to initialise Expat's hash salt during initialization. This could make it easy to conduct denial of service attacks against Expat by constructing an XML document that would cause pathological hash collisions in Expat's internal data structures, consuming large amounts CPU and RAM. The vulnerability exists in Python versions 3.7.0, 3.6.0 through 3.6.6, 3.5.0 through 3.5.6, 3.4.0 through 3.4.9, 2.7.0 through 2.7.15.
Source-reported weakness categories
CWE-335, CWE-665, CWE-909
Source-specific records & product guidance
Sources retain their own attribution and scoring. Follow the original record to confirm affected versions, fixed releases, and configuration conditions.
NIST National Vulnerability Database · NVD-CVE-2018-14647
Open original source · Updated Oct 07, 2026
Only CPE matches marked vulnerable=true are indexed. AND/OR platform conditions must be checked in the original NVD record.
| Vendor | Product / association | Version / bounds |
|---|---|---|
| python | python | * {"versionStartIncluding":"3.6.0","versionEndIncluding":"3.6.6"} |
| python | python | 3.7.0 |
| canonical | ubuntu_linux | 12.04 |
| canonical | ubuntu_linux | 14.04 |
| canonical | ubuntu_linux | 16.04 |
| canonical | ubuntu_linux | 18.04 |
| debian | debian_linux | 8.0 |
| debian | debian_linux | 9.0 |
| fedoraproject | fedora | 30 |
| opensuse | leap | 15.1 |
| redhat | enterprise_linux_desktop | 7.0 |
| redhat | enterprise_linux_server | 7.0 |
| redhat | enterprise_linux_workstation | 7.0 |
Original records & references
- NIST NVD record
- CVE Program record
- access.redhat.com — Third Party Advisory
- access.redhat.com — Third Party Advisory
- access.redhat.com — Third Party Advisory
- bugs.python.org — Issue Tracking, Patch, Vendor Advisory
- bugzilla.redhat.com — Issue Tracking, Third Party Advisory
- lists.apache.org
- lists.debian.org — Mailing List, Third Party Advisory
- lists.debian.org — Mailing List, Third Party Advisory
- lists.fedoraproject.org
- usn.ubuntu.com — Third Party Advisory
- usn.ubuntu.com — Third Party Advisory
- www.debian.org — Third Party Advisory
- www.debian.org — Third Party Advisory
- access.redhat.com — Third Party Advisory
- access.redhat.com — Third Party Advisory
- access.redhat.com — Third Party Advisory
- bugs.python.org — Issue Tracking, Patch, Vendor Advisory
- bugzilla.redhat.com — Issue Tracking, Third Party Advisory
- lists.apache.org
- lists.debian.org — Mailing List, Third Party Advisory
- lists.debian.org — Mailing List, Third Party Advisory
- lists.fedoraproject.org
- usn.ubuntu.com — Third Party Advisory
- usn.ubuntu.com — Third Party Advisory
- www.debian.org — Third Party Advisory
- www.debian.org — Third Party Advisory
PUBLISHED 2018-09-24T20:29:00-04:00
MODIFIED 2026-10-07T15:17:11-04:00
INGESTED 2026-10-08T12:30:34-04:00