CVE-2020-8492: Medium severity Python Python vulnerability

Published Jan 30, 2020
·
Updated

Last updated 25 August 2025

Other sources

Multiple python versions allow an HTTP server to conduct Regular Expression Denial of Service (ReDoS) attacks against a client because of urllib.request.AbstractBasicAuthHandler catastrophic backtracking.

Upstream Issue:

https://bugs.python.org/issue39503

— Red Hat

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.

Python is vulnerable to a denial of service, caused by a flaw in the urllib.request.AbstractBasicAuthHandler. By sending a specially crafted request, a remote attacker could exploit this vulnerability to cause a Regular Expression Denial of Service (ReDoS).

— IBM

Affected Software

25 affected componentsFixes available
redhat/python3<0:3.6.8-17.el7
0:3.6.8-17.el7
redhat/python3<0:3.6.8-31.el8
0:3.6.8-31.el8
redhat/rh-python36-python<0:3.6.12-1.el6
0:3.6.12-1.el6
redhat/rh-python36-python-pip<0:9.0.1-5.el6
0:9.0.1-5.el6
redhat/rh-python36-python-virtualenv<0:15.1.0-3.el6
0:15.1.0-3.el6
redhat/rh-python36-python<0:3.6.12-1.el7
0:3.6.12-1.el7
redhat/rh-python36-python-pip<0:9.0.1-5.el7
0:9.0.1-5.el7
redhat/rh-python36-python-virtualenv<0:15.1.0-3.el7
0:15.1.0-3.el7
debian/python2.7
2.7.18-8+deb11u1
redhat/python<3.8.3
3.8.3
Python Python>=2.7.0<=2.7.17
Python Python>=3.5.0<=3.5.9
Python Python>=3.6.0<=3.6.10
Python Python>=3.7.0<=3.7.6
Python Python>=3.8.0<=3.8.1
openSUSE Leap=15.1
Canonical Ubuntu Linux=12.04
Canonical Ubuntu Linux=14.04
Canonical Ubuntu Linux=16.04
Canonical Ubuntu Linux=18.04
Canonical Ubuntu Linux=19.10
Canonical Ubuntu Linux=20.04
Fedoraproject Fedora=31
Fedoraproject Fedora=32
Debian Debian Linux=9.0

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade redhat/python3 to a version that resolves this vulnerability.

    Fixed in 0:3.6.8-17.el7
  2. Upgrade

    Upgrade redhat/python3 to a version that resolves this vulnerability.

    Fixed in 0:3.6.8-31.el8
  3. Upgrade

    Upgrade redhat/rh-python36-python to a version that resolves this vulnerability.

    Fixed in 0:3.6.12-1.el6
  4. Upgrade

    Upgrade redhat/rh-python36-python-pip to a version that resolves this vulnerability.

    Fixed in 0:9.0.1-5.el6
  5. Upgrade

    Upgrade redhat/rh-python36-python-virtualenv to a version that resolves this vulnerability.

    Fixed in 0:15.1.0-3.el6
  6. Upgrade

    Upgrade redhat/rh-python36-python to a version that resolves this vulnerability.

    Fixed in 0:3.6.12-1.el7
  7. Upgrade

    Upgrade redhat/rh-python36-python-pip to a version that resolves this vulnerability.

    Fixed in 0:9.0.1-5.el7
  8. Upgrade

    Upgrade redhat/rh-python36-python-virtualenv to a version that resolves this vulnerability.

    Fixed in 0:15.1.0-3.el7
  9. Upgrade

    Upgrade debian/python2.7 to a version that resolves this vulnerability.

    Fixed in 2.7.18-8+deb11u1
  10. Upgrade

    Upgrade redhat/python to a version that resolves this vulnerability.

    Fixed in 3.8.3

Event History

Jan 30, 2020
CVE Published
via MITRE·12:00 AM
Data Sourced
via MITRE·12:00 AM
Description
Data Sourced
via NVD·07:15 PM
RemedyDescriptionSeverityWeaknessAffected Software
Aug 3, 2024
Data Sourced
via IBM·10:19 PM
DescriptionSeverityAffected Software
Feb 21, 2026
Data Sourced
via Ubuntu·12:19 AM
RemedyDescriptionSeverityAffected Software
Data Sourced
via Launchpad·12:19 AM
Description

Parent advisories

This vulnerability appears in the following advisories.

Free Weekly Intel

Don't miss critical vulnerabilities

Join thousands of security professionals who receive our weekly digest of trending CVEs, zero-days, and exploited vulnerabilities.

No spam. Unsubscribe anytime.

Frequently Asked Questions

1

What is the vulnerability ID?

The vulnerability ID is CVE-2020-8492.

2

What is the severity of CVE-2020-8492?

The severity of CVE-2020-8492 is medium.

3

What is the description of CVE-2020-8492?

CVE-2020-8492 allows an HTTP server to conduct Regular Expression Denial of Service (ReDoS) attacks against a client.

4

Which software versions are affected by CVE-2020-8492?

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 are affected by CVE-2020-8492.

5

How can I fix CVE-2020-8492?

To fix CVE-2020-8492, update Python to version 3.6.8-17.el7, 3.6.8-31.el8, 3.6.12-1.el6, 9.0.1-5.el6, 15.1.0-3.el6, 3.6.12-1.el7, 9.0.1-5.el7, or 15.1.0-3.el7, or Python to version 3.8.3.

Company

Resources

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203