CVE-2020-8492

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Summary

CVECVE-2020-8492
StatePUBLISHED
Assignermitre
Source PriorityCVE Program / NVD first with legacy fallback
Published2020-01-30 19:15:12 UTC
Updated2026-10-14 09:17:21 UTC
DescriptionPython 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.

Risk And Classification

Primary CVSS: v3.1 6.5 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS: 0.066170000 probability, percentile 0.936850000 (date 2026-10-07)

Problem Types: CWE-400 | n/a | CWE-400 CWE-400 Uncontrolled Resource Consumption

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
3.1ADPDECLARED6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
2.0[email protected]Primary7.1AV:N/AC:M/Au:N/C:N/I:N/A:C

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

CVSS v2.0 Breakdown

Access Vector
Network
Access Complexity
Medium
Authentication
None
Confidentiality
None
Integrity
None
Availability
Complete

AV:N/AC:M/Au:N/C:N/I:N/A:C

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Canonical Ubuntu Linux 12.04 All All All
Operating System Canonical Ubuntu Linux 14.04 All All All
Operating System Canonical Ubuntu Linux 16.04 All All All
Operating System Canonical Ubuntu Linux 18.04 All All All
Operating System Canonical Ubuntu Linux 19.10 All All All
Operating System Canonical Ubuntu Linux 20.04 All All All
Operating System Debian Debian Linux 9.0 All All All
Operating System Fedoraproject Fedora 31 All All All
Operating System Fedoraproject Fedora 32 All All All
Operating System Opensuse Leap 15.1 All All All
Application Python Python All All All All
Application Python Python All All All All
Application Python Python All All All All
Application Python Python All All All All
Application Python Python All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Na N/a affected n/a Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.0 V3.1.5 custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.0 V3.1.5 custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.0 V3.1.5 custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.0 V3.1.5 custom Not specified
ADP Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.0 V3.1.5 custom Not specified

References

ReferenceSourceLinkTags
cert-portal.siemens.com/productcert/html/ssa-398330.html 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e cert-portal.siemens.com
Issue 39503: [security][CVE-2020-8492] Denial of service in urllib.request.AbstractBasicAuthHandler - Python tracker af854a3a-2127-422b-91ae-364da2661108 bugs.python.org Issue Tracking, Vendor Advisory
[SECURITY] [DLA 2280-1] python3.5 security update af854a3a-2127-422b-91ae-364da2661108 lists.debian.org Mailing List, Third Party Advisory
[SECURITY] Fedora 31 Update: python36-3.6.11-1.fc31 - package-announce - Fedora Mailing-Lists af854a3a-2127-422b-91ae-364da2661108 lists.fedoraproject.org
USN-4333-1: Python vulnerabilities | Ubuntu security notices af854a3a-2127-422b-91ae-364da2661108 usn.ubuntu.com Third Party Advisory
[SECURITY] Fedora 32 Update: python3-3.8.3-1.fc32 - package-announce - Fedora Mailing-Lists af854a3a-2127-422b-91ae-364da2661108 lists.fedoraproject.org
Pony Mail! af854a3a-2127-422b-91ae-364da2661108 lists.apache.org
urllib basic auth regex denial of service — Python Security 0.0 documentation af854a3a-2127-422b-91ae-364da2661108 python-security.readthedocs.io Exploit, Third Party Advisory
[SECURITY] Fedora 32 Update: python36-3.6.11-1.fc32 - package-announce - Fedora Mailing-Lists af854a3a-2127-422b-91ae-364da2661108 lists.fedoraproject.org
[security-announce] openSUSE-SU-2020:0274-1: moderate: Security update f af854a3a-2127-422b-91ae-364da2661108 lists.opensuse.org Third Party Advisory
[SECURITY] Fedora 31 Update: python38-3.8.3-1.fc31 - package-announce - Fedora Mailing-Lists af854a3a-2127-422b-91ae-364da2661108 lists.fedoraproject.org
bpo-39503: Fix urllib basic auth regex by vstinner · Pull Request #18284 · python/cpython · GitHub af854a3a-2127-422b-91ae-364da2661108 github.com Patch, Third Party Advisory
CVE-2020-8492 Python Vulnerability in NetApp Products | NetApp Product Security af854a3a-2127-422b-91ae-364da2661108 security.netapp.com Third Party Advisory
Python: Denial of Service (GLSA 202005-09) — Gentoo security af854a3a-2127-422b-91ae-364da2661108 security.gentoo.org Third Party Advisory
[SECURITY] [DLA 3432-1] python2.7 security update af854a3a-2127-422b-91ae-364da2661108 lists.debian.org
Pony Mail! af854a3a-2127-422b-91ae-364da2661108 lists.apache.org
USN-4333-2: Python vulnerabilities | Ubuntu security notices af854a3a-2127-422b-91ae-364da2661108 usn.ubuntu.com Third Party Advisory
[SECURITY] Fedora 31 Update: python38-3.8.3-1.fc31 - package-announce - Fedora Mailing-Lists MITRE lists.fedoraproject.org
[SECURITY] Fedora 32 Update: python36-3.6.11-1.fc32 - package-announce - Fedora Mailing-Lists MITRE lists.fedoraproject.org
[SECURITY] Fedora 32 Update: python3-3.8.3-1.fc32 - package-announce - Fedora Mailing-Lists MITRE lists.fedoraproject.org
[SECURITY] Fedora 31 Update: python36-3.6.11-1.fc31 - package-announce - Fedora Mailing-Lists MITRE lists.fedoraproject.org
Pony Mail! MITRE lists.apache.org
Pony Mail! MITRE lists.apache.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Legacy QID Mappings

  • 159654 Oracle Enterprise Linux Security Update for python38:3.8 (ELSA-2020-4641)
  • 181802 Debian Security Update for python2.7 (DLA 3432-1)
  • 198293 Ubuntu Security Notification for Python2.7, Python3.7, Python3.8 Vulnerabilities (USN-4754-3)
  • 198611 Ubuntu Security Notification for Python Vulnerabilities (USN-5200-1)
  • 296073 Oracle Solaris 11.4 Support Repository Update (SRU) 24.75.2 Missing (CPUJUL2020)
  • 356280 Amazon Linux Security Advisory for python38 : ALASPYTHON3.8-2023-006
  • 356582 Amazon Linux Security Advisory for python38 : ALAS2PYTHON3.8-2023-006
  • 376090 IBM Cognos Analytics Multiple Vulnerabilities (6491661)
  • 377257 Alibaba Cloud Linux Security Update for python3 (ALINUX2-SA-2020:0137)
  • 377387 Alibaba Cloud Linux Security Update for python3 (ALINUX3-SA-2021:0080)
  • 500591 Alpine Linux Security Update for python3
  • 504341 Alpine Linux Security Update for python3
  • 690114 Free Berkeley Software Distribution (FreeBSD) Security Update for tauthon (c7855866-c511-11eb-ae1d-b42e991fc52e)
  • 690464 Free Berkeley Software Distribution (FreeBSD) Security Update for python (2cb21232-fb32-11ea-a929-a4bf014bf5f7)
  • 750463 OpenSUSE Security Update for python3 (openSUSE-SU-2020:2333-1)
  • 750464 OpenSUSE Security Update for python3 (openSUSE-SU-2020:2332-1)
  • 752957 SUSE Enterprise Linux Security Update for python3 (SUSE-SU-2022:4281-1)
  • 770068 Red Hat OpenShift Container Platform 4.6 Security Update (RHSA-2021:0436)
  • 940166 AlmaLinux Security Update for python3 (ALSA-2020:4433)
  • 940211 AlmaLinux Security Update for python38:3.8 (ALSA-2020:4641)
  • 960347 Rocky Linux Security Update for python38:3.8 (RLSA-2020:4641)

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