High
Security advisory
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2018-14647
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 08:07 UTC · Revision 1
Source evidence
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.
osv:CVE-2018-14647
Complete source record
{
"id": "08d7085dc4c754a6ed92745175c1ec0f3ec568ff5a4b9bdf045a6e04595f97d5",
"url": "https://osv.dev/vulnerability/CVE-2018-14647",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2018-14647",
"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.",
"evidence": "osv:CVE-2018-14647",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2018-14647",
"aliases": [
"CVE-2018-14647",
"PSF-2018-5"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
}
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"database_specific": {
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}
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],
"modified": "2026-10-24T10:31:03.092007330Z",
"provider": "osv",
"references": [
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"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RBJCB2HWOJLP3L7CUQHJHNBHLSVOXJE5/",
"https://access.redhat.com/errata/RHSA-2019:1260",
"https://access.redhat.com/errata/RHSA-2019:2030",
"https://access.redhat.com/errata/RHSA-2019:3725",
"https://lists.debian.org/debian-lts-announce/2019/06/msg00022.html",
"https://lists.debian.org/debian-lts-announce/2019/06/msg00023.html",
"https://usn.ubuntu.com/3817-1/",
"https://usn.ubuntu.com/3817-2/",
"https://www.debian.org/security/2018/dsa-4306",
"https://www.debian.org/security/2018/dsa-4307",
"https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-14647",
"https://bugs.python.org/issue34623"
],
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},
"source_id": "core-osv",
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"published_at": "2018-09-25T00:29:00.703+00:00"
}