Medium
Security advisory
Python 2.7 through 2.7.17, 3.5 through 3.5.9, 3.6 through 3.6.10, 3.7 through 3.7.6, and 3.8 through 3.8.1 allows an HTTP server to conduct Regular Expression Denial of Service (ReDoS) attacks against a client because of urllib.request.AbstractBasicAuthHandler catastrophic backtracking.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2020-8492
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 11:14 UTC · Revision 1
Source evidence
Python 2.7 through 2.7.17, 3.5 through 3.5.9, 3.6 through 3.6.10, 3.7 through 3.7.6, and 3.8 through 3.8.1 allows an HTTP server to conduct Regular Expression Denial of Service (ReDoS) attacks against a client because of urllib.request.AbstractBasicAuthHandler catastrophic backtracking.
osv:CVE-2020-8492
Complete source record
{
"id": "27fb5ffe1f4b3c90e09c7ae917ef9ea9539d715d25580b0bf4dc3d1456ccf55f",
"url": "https://osv.dev/vulnerability/CVE-2020-8492",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2020-8492",
"summary": "Python 2.7 through 2.7.17, 3.5 through 3.5.9, 3.6 through 3.6.10, 3.7 through 3.7.6, and 3.8 through 3.8.1 allows an HTTP server to conduct Regular Expression Denial of Service (ReDoS) attacks against a client because of urllib.request.AbstractBasicAuthHandler catastrophic backtracking.",
"evidence": "osv:CVE-2020-8492",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2020-8492",
"aliases": [
"BIT-libpython-2020-8492",
"BIT-python-2020-8492",
"BIT-python-min-2020-8492",
"CVE-2020-8492",
"PSF-2020-8"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/python/cpython",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"last_affected": "c2f86d86e6c8f5fd1ef602128b537a48f3f5c063"
},
{
"introduced": "2e789a1f1d84b343a996e8654590703b5fbdd441"
},
{
"last_affected": "e5f6aba872e66bfd86eb592214696a519cded197"
},
{
"introduced": "5c4568a05a0a62b5947c55f68f9f2ecfb90a4f12"
},
{
"last_affected": "02dff8b01100e7cd6d4c93be27202ccb4ea05811"
},
{
"introduced": "1bf9cc509326bc42cd8cb1650eb9bf64550d817e"
},
{
"last_affected": "43364a7ae01fbe4288ef42622259a0038ce1edcc"
},
{
"introduced": "fa919fdf2583bdfead1df00e842f24f30b2a34bf"
},
{
"last_affected": "1b293b60067f6f4a95984d064ce0f6b6d34c1216"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:python:python:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "2.7.0"
},
{
"last_affected": "2.7.17"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:python:python:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "3.5.0"
},
{
"last_affected": "3.5.9"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:python:python:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "3.6.0"
},
{
"last_affected": "3.6.10"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:python:python:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "3.7.0"
},
{
"last_affected": "3.7.6"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:python:python:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "3.8.0"
},
{
"last_affected": "3.8.1"
}
],
"source": "CPE_RANGE"
}
]
}
}
],
"versions": [
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"v3.7.6",
"v3.6.10",
"v3.6.10rc1",
"v3.7.6rc1",
"v3.5.9",
"v3.5.8",
"v2.7.17",
"v3.5.8rc2",
"v3.5.8rc1",
"v2.7.17rc1",
"v3.8.0rc1",
"v3.6.9",
"v3.6.9rc1",
"v3.7.3rc1",
"v3.5.7",
"v3.5.7rc1",
"v2.7.16rc1",
"v3.6.8",
"v3.7.2rc1",
"v3.6.8rc1",
"v3.5.6",
"v3.5.6rc1",
"v3.7.0rc1",
"v3.6.6rc1",
"v3.7.0b5",
"v3.7.0b4",
"v2.7.15rc1",
"v3.7.0b3",
"v3.7.0b2",
"v3.5.5",
"v3.5.5rc1",
"v3.7.0b1",
"v3.7.0a2",
"v3.5.4",
"v3.5.4rc1",
"v3.6.2rc1",
"v3.5.3",
"v3.5.3rc1",
"v3.6.0rc1",
"v2.7.13rc1",
"v3.6.0b4",
"v3.6.0b3",
"v3.6.0b1",
"v3.6.0a3",
"v3.5.2",
"v3.5.2rc1",
"v2.7.12rc1",
"v3.5.1rc1",
"v2.7.11rc1",
"v3.5.0rc3",
"v3.5.0rc2",
"v3.5.0rc1",
"v3.5.0b4",
"v3.5.0b3",
"v3.5.0b1",
"v2.7.10rc1",
"v3.5.0a4",
"v3.5.0a3",
"v3.5.0a2",
"v3.5.0a1",
"v2.7.9rc1",
"v2.7.8",
"v3.4.0b3",
"v3.4.0b2",
"v3.4.0b1",
"v2.7.6rc1",
"v3.4.0a4",
"v3.4.0a3",
"v3.4.0a2",
"v3.4.0a1",
"v2.7.5",
"v2.7.4rc1",
"v3.3.0rc3",
"v3.3.0rc2",
"v3.3.0rc1",
"v3.3.0b2",
"v3.3.0b1",
"v3.3.0a4",
"v3.3.0a3",
"v3.3.0a2",
"v2.7.3rc1",
"v2.7.2rc1",
"v2.7",
"v3.2rc3",
"v3.2rc2",
"v3.2rc1",
"v3.2b2",
"v3.2b1",
"v2.7.1",
"v2.7.1rc1",
"v3.2a4",
"v3.2a3",
"v3.2a2",
"v3.2a1",
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"v2.7rc1",
"v2.7b2",
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"v2.7a4",
"v2.7a3",
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"v2.7a1",
"v3.1",
"v3.1rc2",
"v3.1rc1",
"v3.1b1",
"v3.1a2",
"v3.1a1",
"v3.0rc3",
"v3.0rc2",
"v2.6",
"v2.6rc2",
"v3.0rc1",
"v2.6rc1",
"v3.0b3",
"v2.6b3",
"v2.6b2",
"v3.0b2",
"v2.6b1",
"v3.0b1",
"v2.6a3",
"v3.0a5",
"v2.6a2",
"v3.0a4",
"v3.0a3",
"v2.6a1",
"v3.0a2",
"v3.0a1",
"v2.5b3",
"v2.5b2",
"v2.5b1",
"v2.5a2",
"v2.5a1",
"v2.5a0",
"v2.4",
"v2.4c1",
"v2.4b2",
"v2.4b1",
"v2.4a3",
"v2.4a2",
"v2.4a1",
"v2.3c2",
"v2.3c1",
"v2.2a3",
"v2.1",
"v2.1c2",
"v2.1c1",
"v2.1b2",
"v2.1b1",
"v2.1a2",
"v2.1a1",
"v2.0",
"v2.0c1",
"v2.0b2",
"v2.0b1",
"v1.6a2",
"v1.6a1",
"v1.5.2",
"v1.5.2c1",
"v1.5.2b2",
"v1.5.2b1",
"v1.5.2a2",
"v1.5.2a1",
"v1.5.1",
"v1.5",
"v1.5b2",
"v1.5b1",
"v1.5a4",
"v1.5a3",
"v1.5a2",
"v1.5a1",
"v1.4",
"v1.4b3",
"v1.4b2",
"v1.4b1",
"v1.3",
"v1.3b1",
"v1.2",
"v1.2b4",
"v1.2b3",
"v1.2b2",
"v1.2b1",
"v1.1.1",
"v1.1",
"v1.0.2",
"v1.0.1",
"v0.9.9",
"v0.9.8"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-8492.json"
}
}
],
"modified": "2026-10-20T10:53:31.818057643Z",
"provider": "osv",
"references": [
"https://cert-portal.siemens.com/productcert/html/ssa-398330.html",
"https://lists.apache.org/thread.html/rdb31a608dd6758c6093fd645aea3fbf022dd25b37109b6aaea5bc0b5%40%3Ccommits.cassandra.apache.org%3E",
"https://lists.apache.org/thread.html/rfec113c733162b39633fd86a2d0f34bf42ac35f711b3ec1835c774da%40%3Ccommits.cassandra.apache.org%3E",
"https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html",
"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7WOKDEXLYW5UQ4S7PA7E37IITOC7C56J/",
"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/A5NSAX4SC3V64PGZUPH7PRDLSON34Q5A/",
"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/APGWEMYZIY5VHLCSZ3HD67PA5Z2UQFGH/",
"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UESGYI5XDAHJBATEZN3MHNDUBDH47AS6/",
"https://lists.debian.org/debian-lts-announce/2020/07/msg00011.html",
"https://security.gentoo.org/glsa/202005-09",
"https://security.netapp.com/advisory/ntap-20200221-0001/",
"https://usn.ubuntu.com/4333-1/",
"https://usn.ubuntu.com/4333-2/",
"https://bugs.python.org/issue39503",
"https://github.com/python/cpython/pull/18284",
"https://python-security.readthedocs.io/vuln/urllib-basic-auth-regex.html"
],
"provider_metadata": {
"unresolved_ranges": [
{
"cpes": [
"cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:*:*:*:*",
"cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:esm:*:*:*",
"cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:*",
"cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*",
"cpe:2.3:o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:*",
"cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:*"
],
"vendor_product": "canonical:ubuntu_linux",
"extracted_events": [
{
"range": [
{
"introduced": "12.04"
},
{
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},
{
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},
{
"last_affected": "14.04"
},
{
"introduced": "16.04"
},
{
"last_affected": "16.04"
},
{
"introduced": "18.04"
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{
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},
{
"introduced": "19.10"
},
{
"last_affected": "19.10"
},
{
"introduced": "20.04"
},
{
"last_affected": "20.04"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*"
],
"vendor_product": "debian:debian_linux",
"extracted_events": [
{
"range": [
{
"introduced": "9.0"
},
{
"last_affected": "9.0"
}
],
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}
]
},
{
"cpes": [
"cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*",
"cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*"
],
"vendor_product": "fedoraproject:fedora",
"extracted_events": [
{
"range": [
{
"introduced": "31"
},
{
"last_affected": "31"
},
{
"introduced": "32"
},
{
"last_affected": "32"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*"
],
"vendor_product": "opensuse:leap",
"extracted_events": [
{
"range": [
{
"introduced": "15.1"
},
{
"last_affected": "15.1"
}
],
"source": "CPE_STRING"
}
]
}
]
}
},
"related_cves": [
{
"value": "CVE-2020-8492",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 384398,
"published_at": "2020-01-30T19:15:12.103+00:00"
}