high
7.5
CWE
400 20
Advisory Published
CVE Published
Advisory Published
Updated

CVE-2020-28493: Regular Expression Denial of Service (ReDoS)

First published: Mon Feb 01 2021(Updated: )

A flaw was found in python-jinja2. The ReDOS vulnerability of the regex is mainly due to the sub-pattern [a-zA-Z0-9._-]+.[a-zA-Z0-9._-]+. This issue can be mitigated by Markdown to format user content instead of the urlize filter, or by implementing request timeouts and limiting process memory.

Credit: report@snyk.io report@snyk.io

Affected SoftwareAffected VersionHow to fix
pip/jinja2<2.11.3
2.11.3
redhat/python-jinja2<0:2.10.1-3.el8
0:2.10.1-3.el8
redhat/python27-babel<0:0.9.6-10.el7
0:0.9.6-10.el7
redhat/python27-python<0:2.7.18-3.el7
0:2.7.18-3.el7
redhat/python27-python-jinja2<0:2.6-16.el7
0:2.6-16.el7
redhat/python27-python-pygments<0:1.5-5.el7
0:1.5-5.el7
redhat/rh-python38-babel<0:2.7.0-12.el7
0:2.7.0-12.el7
redhat/rh-python38-python<0:3.8.11-2.el7
0:3.8.11-2.el7
redhat/rh-python38-python-cryptography<0:2.8-5.el7
0:2.8-5.el7
redhat/rh-python38-python-jinja2<0:2.10.3-6.el7
0:2.10.3-6.el7
redhat/rh-python38-python-lxml<0:4.4.1-7.el7
0:4.4.1-7.el7
redhat/rh-python38-python-pip<0:19.3.1-2.el7
0:19.3.1-2.el7
redhat/rh-python38-python-urllib3<0:1.25.7-7.el7
0:1.25.7-7.el7
Palletsprojects Jinja<2.11.3
Fedoraproject Fedora=33
redhat/jinja2<2.11.3
2.11.3
ubuntu/jinja2<2.8-1ubuntu0.1+
2.8-1ubuntu0.1+
ubuntu/jinja2<2.10-1ubuntu0.18.04.1+
2.10-1ubuntu0.18.04.1+
ubuntu/jinja2<2.10.1-2ubuntu0.2
2.10.1-2ubuntu0.2
ubuntu/jinja2<2.11.3
2.11.3
ubuntu/jinja2<2.7.2-2ubuntu0.1~
2.7.2-2ubuntu0.1~
debian/jinja2<=2.10-2<=2.10-2+deb10u1
2.11.3-1
3.1.2-1
3.1.3-1

Remedy

If using the jinja2 library as a developer, this flaw can be mitigated by not using the vulnerable urlize() filter, and instead, using Markdown to format user content.

Remedy

https://github.com/pallets/jinja/pull/1343

Remedy

https://github.com/pallets/jinja/commit/15ef8f09b659f9100610583938005a7a10472d4d

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Reference Links

Parent vulnerabilities

(Appears in the following advisories)

Frequently Asked Questions

  • What is CVE-2020-28493?

    CVE-2020-28493 is a vulnerability in the Python Jinja2 package that allows for ReDoS attacks due to the use of multiple wildcards in the regex operator.

  • What is the severity of CVE-2020-28493?

    CVE-2020-28493 has a severity rating of high with a score of 7.

  • How does CVE-2020-28493 affect the python-jinja2 package?

    CVE-2020-28493 affects the python-jinja2 package versions 0.0.0 to 2.11.3.

  • What is the risk of CVE-2020-28493?

    CVE-2020-28493 poses a risk of denial of service attacks through ReDoS vulnerabilities.

  • How can I mitigate CVE-2020-28493?

    You can mitigate CVE-2020-28493 by updating the python-jinja2 package to version 2.11.3 or higher.

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