CVE-2019-9636: Critical severity Python Python vulnerability
A vulnerability was found in Python 2.7.x through 2.7.16 and 3.x through 3.7.2. An improper Handling of Unicode Encoding (with an incorrect netloc) during NFKC normalization could lead to an Information Disclosure (credentials, cookies, etc. that are cached against a given hostname) in the urllib.parse.urlsplit, urllib.parse.urlparse components. A specially crafted URL could be incorrectly parsed to locate cookies or authentication data and send that information to a different host than when parsed correctly.
References: https://bugs.python.org/issue36216 https://python-security.readthedocs.io/vuln/urlsplit-nfkc-normalization.html
Uptream Patch: https://github.com/python/cpython/pull/12201
Other sources
It was discovered that python's functions urllib.parse.urlsplit and urllib.parse.urlparse do not properly handle URLs encoded with Punycode/Internationalizing Domain Names in Applications (IDNA), which may result in a wrong domain name (specifically the netloc component of URL - user@domain:port) being returned by those functions. When an application parses user-supplied URLs to store cookies, authentication credentials, or other kind of information, it is possible for an attacker to provide specially crafted URLs to make the application locate host-related information (e.g. cookies, authentication data) and send them to a different host than where it should, unlike if the URLs had been correctly parsed. The result of an attack may vary based on the application.
Python 2.7.x through 2.7.16 and 3.x through 3.7.2 is affected by: Improper Handling of Unicode Encoding (with an incorrect netloc) during NFKC normalization. The impact is: Information disclosure (credentials, cookies, etc. that are cached against a given hostname). The components are: urllib.parse.urlsplit, urllib.parse.urlparse. The attack vector is: A specially crafted URL could be incorrectly parsed to locate cookies or authentication data and send that information to a different host than when parsed correctly. This is fixed in: v2.7.17, v2.7.17rc1, v2.7.18, v2.7.18rc1; v3.5.10, v3.5.10rc1, v3.5.7, v3.5.8, v3.5.8rc1, v3.5.8rc2, v3.5.9; v3.6.10, v3.6.10rc1, v3.6.11, v3.6.11rc1, v3.6.12, v3.6.9, v3.6.9rc1; v3.7.3, v3.7.3rc1, v3.7.4, v3.7.4rc1, v3.7.4rc2, v3.7.5, v3.7.5rc1, v3.7.6, v3.7.6rc1, v3.7.7, v3.7.7rc1, v3.7.8, v3.7.8rc1, v3.7.9.
Affected Software
Remediation
Patch Available
Patch Available
Event History
Parent advisories
This vulnerability appears in the following advisories.
Frequently Asked Questions
What is the severity of CVE-2019-9636?
CVE-2019-9636 is considered a moderate severity vulnerability due to potential information disclosure.
How do I fix CVE-2019-9636?
To fix CVE-2019-9636, update to Python version 2.7.17 or higher, or 3.5.7, 3.6.9, or 3.7.3.
What systems are affected by CVE-2019-9636?
CVE-2019-9636 affects Python versions 2.7.x from 2.7.0 to 2.7.16 and 3.x from 3.0.0 to 3.7.2.
What are the potential impacts of CVE-2019-9636?
The potential impact of CVE-2019-9636 includes the disclosure of sensitive information such as credentials and cookies.
Is there a workaround for CVE-2019-9636?
There is no recommended workaround for CVE-2019-9636, and users are encouraged to apply the updates as soon as possible.