RHSA-2021:3254 - Security Advisory

Topic

An update for rh-python38-babel, rh-python38-python, rh-python38-python-cryptography, rh-python38-python-jinja2, rh-python38-python-lxml, rh-python38-python-pip, and rh-python38-python-urllib3 is now available for Red Hat Software Collections.

Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

Python is an interpreted, interactive, object-oriented programming language, which includes modules, classes, exceptions, very high level dynamic data types and dynamic typing. Python supports interfaces to many system calls and libraries, as well as to various windowing systems.

The following packages have been upgraded to a later upstream version: rh-python38-python (3.8.11). (BZ#1969523)

Security Fix(es):

• python-cryptography: Bleichenbacher timing oracle attack against RSA decryption (CVE-2020-25659)
• python: Unsafe use of eval() on data retrieved via HTTP in the test suite (CVE-2020-27619)
• python-lxml: mXSS due to the use of improper parser (CVE-2020-27783)
• python-jinja2: ReDoS vulnerability due to the sub-pattern (CVE-2020-28493)
• python-cryptography: Large inputs for symmetric encryption can trigger integer overflow leading to buffer overflow (CVE-2020-36242)
• python: Stack-based buffer overflow in PyCArg_repr in _ctypes/callproc.c (CVE-2021-3177)
• python: Information disclosure via pydoc (CVE-2021-3426)
• python-babel: Relative path traversal allows attacker to load arbitrary locale files and execute arbitrary code (CVE-2021-20095)
• python: Web cache poisoning via urllib.parse.parse_qsl and urllib.parse.parse_qs by using a semicolon in query parameters (CVE-2021-23336)
• python-lxml: Missing input sanitization for formaction HTML5 attributes may lead to XSS (CVE-2021-28957)
• python-ipaddress: Improper input validation of octal strings (CVE-2021-29921)
• python-urllib3: ReDoS in the parsing of authority part of URL (CVE-2021-33503)
• python-pip: Incorrect handling of unicode separators in git references (CVE-2021-3572)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Additional information

• Changes in the default separator for the Python urllib parsing functions

To mitigate the Web Cache Poisoning CVE-2021-23336 in the Python urllib library, the default separator for the urllib.parse.parse_qsl and urllib.parse.parse_qs functions is being changed from both ampersand (&) and semicolon (;) to only an ampersand.

The change of the default separator is potentially backwards incompatible, therefore Red Hat provides a way to configure the behavior in Python packages where the default separator has been changed. In addition, the affected urllib parsing functions issue a warning if they detect that a customer’s application has been affected by the change.

For more information, see the Knowledgebase article "Mitigation of Web Cache Poisoning in the Python urllib library (CVE-2021-23336)" linked from the References section.

• The Python "ipaddress" module no longer allows leading zeros in IPv4 addresses

To mitigate CVE-2021-29921, the Python "ipaddress" module now rejects IPv4 addresses with leading zeros with an "AddressValueError: Leading zeros are not permitted" error.

Customers who rely on the previous behavior can pre-process their IPv4 address inputs to strip the leading zeros off. For details, see the Red Hat Software Collections 3.7 Release Notes.

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Software Collections (for RHEL Server) 1 for RHEL 7.7 x86_64
• Red Hat Software Collections (for RHEL Server for System Z) 1 for RHEL 7.7 s390x
• Red Hat Software Collections (for RHEL Server for IBM Power LE) 1 for RHEL 7.7 ppc64le
• Red Hat Software Collections (for RHEL Server) 1 for RHEL 7 x86_64
• Red Hat Software Collections (for RHEL Server for System Z) 1 for RHEL 7 s390x
• Red Hat Software Collections (for RHEL Server for IBM Power LE) 1 for RHEL 7 ppc64le
• Red Hat Software Collections (for RHEL Workstation) 1 for RHEL 7 x86_64

Fixes

• BZ - 1889886 - CVE-2020-27619 python: Unsafe use of eval() on data retrieved via HTTP in the test suite
• BZ - 1889988 - CVE-2020-25659 python-cryptography: Bleichenbacher timing oracle attack against RSA decryption
• BZ - 1901633 - CVE-2020-27783 python-lxml: mXSS due to the use of improper parser
• BZ - 1918168 - CVE-2021-3177 python: Stack-based buffer overflow in PyCArg_repr in _ctypes/callproc.c
• BZ - 1926226 - CVE-2020-36242 python-cryptography: Large inputs for symmetric encryption can trigger integer overflow leading to buffer overflow
• BZ - 1928707 - CVE-2020-28493 python-jinja2: ReDoS vulnerability due to the sub-pattern
• BZ - 1928904 - CVE-2021-23336 python: Web cache poisoning via urllib.parse.parse_qsl and urllib.parse.parse_qs by using a semicolon in query parameters
• BZ - 1935913 - CVE-2021-3426 python: Information disclosure via pydoc
• BZ - 1941534 - CVE-2021-28957 python-lxml: Missing input sanitization for formaction HTML5 attributes may lead to XSS
• BZ - 1955615 - CVE-2021-20095 python-babel: Relative path traversal allows attacker to load arbitrary locale files and execute arbitrary code
• BZ - 1957458 - CVE-2021-29921 python-ipaddress: Improper input validation of octal strings
• BZ - 1962856 - CVE-2021-3572 python-pip: Incorrect handling of unicode separators in git references
• BZ - 1968074 - CVE-2021-33503 python-urllib3: ReDoS in the parsing of authority part of URL
• BZ - 1969523 - Update the python interpreter to the latest bugfix release 3.8.10 [rhel-3.7.0.z]

CVEs

• CVE-2020-25659
• CVE-2020-27619
• CVE-2020-27783
• CVE-2020-28493
• CVE-2020-36242
• CVE-2021-3177
• CVE-2021-3426
• CVE-2021-3572
• CVE-2021-3733
• CVE-2021-20095
• CVE-2021-23336
• CVE-2021-28957
• CVE-2021-29921
• CVE-2021-33503

References

• https://access.redhat.com/security/updates/classification/#moderate
• https://access.redhat.com/articles/5860431
• https://access.redhat.com/documentation/en-us/red_hat_software_collections/3/html-single/3.7_release_notes/index#sect-RHSCL-Other-notes