Medium
Security advisory
An issue was discovered in Django 2.0 before 2.0.3, 1.11 before 1.11.11, and 1.8 before 1.8.19. If django.utils.text.Truncator's chars() and words() methods were passed the html=True argument, they were extremely slow to evaluate certain inputs due to a catastrophic backtracking vulnerability in a regular expression. The chars() and words() methods are used to implement the truncatechars_html and truncatewords_html template filters, which were thus vulnerable.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2018-7537
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 04:34 UTC · Revision 1
Source evidence
An issue was discovered in Django 2.0 before 2.0.3, 1.11 before 1.11.11, and 1.8 before 1.8.19. If django.utils.text.Truncator's chars() and words() methods were passed the html=True argument, they were extremely slow to evaluate certain inputs due to a catastrophic backtracking vulnerability in a regular expression. The chars() and words() methods are used to implement the truncatechars_html and truncatewords_html template filters, which were thus vulnerable.
osv:CVE-2018-7537
Complete source record
{
"id": "d1ca639bbab9cb53cb53589a0ce9dd7e7d2517ee4b743dc8dda6db7e2e13d71c",
"url": "https://osv.dev/vulnerability/CVE-2018-7537",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2018-7537",
"summary": "An issue was discovered in Django 2.0 before 2.0.3, 1.11 before 1.11.11, and 1.8 before 1.8.19. If django.utils.text.Truncator's chars() and words() methods were passed the html=True argument, they were extremely slow to evaluate certain inputs due to a catastrophic backtracking vulnerability in a regular expression. The chars() and words() methods are used to implement the truncatechars_html and truncatewords_html template filters, which were thus vulnerable.",
"evidence": "osv:CVE-2018-7537",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2018-7537",
"aliases": [
"CVE-2018-7537",
"GHSA-2f9x-5v75-3qv4",
"PYSEC-2018-6"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/django/django",
"type": "GIT",
"events": [
{
"introduced": "6a0dc2176f4ebf907e124d433411e52bba39a28e"
},
{
"fixed": "c686dd8e6bb3817bcf04b8f13c025b4d3c3dc6dc"
},
{
"introduced": "c669cf279ae7b3e02a61db4fb077030a4db80e4f"
},
{
"fixed": "1cc5aceac0a73468a6d1a671b9c86423e5bcf011"
},
{
"introduced": "8c85c8692240e5ae4b568eb4272475fe1fa4b059"
},
{
"fixed": "2d73ffc6f96e399716a1ed3f58acd4e99afa3d33"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:djangoproject:django:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "1.8"
},
{
"fixed": "1.8.19"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:djangoproject:django:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "1.11"
},
{
"fixed": "1.11.11"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:djangoproject:django:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "2.0"
},
{
"fixed": "2.0.3"
}
],
"source": "CPE_RANGE"
}
]
}
}
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2018-7537.json"
}
}
],
"modified": "2026-10-24T10:30:20.137795772Z",
"provider": "osv",
"references": [
"https://access.redhat.com/errata/RHSA-2018:2927",
"https://access.redhat.com/errata/RHSA-2019:0265",
"https://lists.debian.org/debian-lts-announce/2018/03/msg00006.html",
"https://usn.ubuntu.com/3591-1/",
"https://www.debian.org/security/2018/dsa-4161",
"https://www.djangoproject.com/weblog/2018/mar/06/security-releases/"
],
"provider_metadata": {
"unresolved_ranges": [
{
"cpes": [
"cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*",
"cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*",
"cpe:2.3:o:canonical:ubuntu_linux:17.10:*:*:*:*:*:*:*"
],
"vendor_product": "canonical:ubuntu_linux",
"extracted_events": [
{
"range": [
{
"introduced": "14.04"
},
{
"last_affected": "14.04"
},
{
"introduced": "16.04"
},
{
"last_affected": "16.04"
},
{
"introduced": "17.10"
},
{
"last_affected": "17.10"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:debian:debian_linux:7.0:*:*:*:*:*:*:*",
"cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*",
"cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*"
],
"vendor_product": "debian:debian_linux",
"extracted_events": [
{
"range": [
{
"introduced": "7.0"
},
{
"last_affected": "7.0"
},
{
"introduced": "8.0"
},
{
"last_affected": "8.0"
},
{
"introduced": "9.0"
},
{
"last_affected": "9.0"
}
],
"source": "CPE_STRING"
}
]
}
]
}
},
"related_cves": [
{
"value": "CVE-2018-7537",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 430197,
"published_at": "2018-03-09T20:29:00.66+00:00"
}