Avoid infinite loop when reading specially crafted TAR files (CVE-2019-20907)

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website.
Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Python 3.9.0b5 update. Contains security fix for CVE-2019-20907. [Full changelog](https://docs.python.org/3.9/whatsnew/changelog.html#python- 3-9-0-beta-5). Large autogenerated modules (`pydoc_data` and several encodings) are now present as `pyc` (optimization 0) files only.

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website.
Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Security fix for CVE-2019-20907, CVE-2020-14422.

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website.
Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The remote MiracleLinux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the AXSA:2021-1204:01 advisory.

    * python: XSS vulnerability in the documentation XML-RPC server in server_title field (CVE-2019-16935)
      * python: infinite loop in the tarfile module via crafted TAR archive (CVE-2019-20907)
      * python: wrong backtracking in urllib.request.AbstractBasicAuthHandler allows for a ReDoS     (CVE-2020-8492)
      * python: DoS via inefficiency in IPv{4,6}Interface classes (CVE-2020-14422)

Tenable has extracted the preceding description block directly from the MiracleLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of python26 installed on the remote host is prior to 2.6.9-2.92. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS-2025-1972 advisory.

    A CRLF injection flaw was discovered in python in the way URLs are handled when doing an HTTP/HTTPS     connection (e.g. through urlopen() or HTTPConnection). An attacker who can control the url parameter     passed to urlopen method in the urllib/urllib2 modules can inject CRLF sequences and HTTP headers by     abusing the host part of the URL. (CVE-2019-18348)

    A flaw was found in python. In Lib/tarfile.py an attacker is able to craft a TAR archive leading to an     infinite loop when opened by tarfile.open, because _proc_pax lacks header validation. (CVE-2019-20907)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Alibaba Cloud Linux 3 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALINUX3-SA-2021:0080 advisory.

    Package updates are available for Alibaba Cloud Linux 3 that fix the following vulnerabilities:

    CVE-2019-10160:
    A security regression of CVE-2019-9636 was discovered in python since commit     d537ab0ff9767ef024f26246899728f0116b1ec3 affecting versions 2.7, 3.5, 3.6, 3.7 and from v3.8.0a4 through     v3.8.0b1, which still allows an attacker to exploit CVE-2019-9636 by abusing the user and password parts     of a URL. 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.

    CVE-2019-16056:
    An issue was discovered in Python through 2.7.16, 3.x through 3.5.7, 3.6.x through 3.6.9, and 3.7.x     through 3.7.4. The email module wrongly parses email addresses that contain multiple @ characters. An     application that uses the email module and implements some kind of checks on the From/To headers of a     message could be tricked into accepting an email address that should be denied. An attack may be the same     as in CVE-2019-11340; however, this CVE applies to Python more generally.

    CVE-2019-16935:
    The documentation XML-RPC server in Python through 2.7.16, 3.x through 3.6.9, and 3.7.x through 3.7.4 has     XSS via the server_title field. This occurs in Lib/DocXMLRPCServer.py in Python 2.x, and in     Lib/xmlrpc/server.py in Python 3.x. If set_server_title is called with untrusted input, arbitrary     JavaScript can be delivered to clients that visit the http URL for this server.

    CVE-2019-20907:
    In Lib/tarfile.py in Python through 3.8.3, an attacker is able to craft a TAR archive leading to an     infinite loop when opened by tarfile.open, because _proc_pax lacks header validation.

    CVE-2019-5010:
    An exploitable denial-of-service vulnerability exists in the X509 certificate parser of Python.org Python     2.7.11 / 3.6.6. A specially crafted X509 certificate can cause a NULL pointer dereference, resulting in a     denial of service. An attacker can initiate or accept TLS connections using crafted certificates to     trigger this vulnerability.

    CVE-2019-9636:
    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.

    CVE-2019-9947:
    An issue was discovered in urllib2 in Python 2.x through 2.7.16 and urllib in Python 3.x through 3.7.3.
    CRLF injection is possible if the attacker controls a url parameter, as demonstrated by the first argument     to urllib.request.urlopen with \r\n (specifically in the path component of a URL that lacks a ? character)     followed by an HTTP header or a Redis command. This is similar to the CVE-2019-9740 query string issue.
    This is fixed in: v2.7.17, v2.7.17rc1, v2.7.18, v2.7.18rc1; v3.5.10, v3.5.10rc1, 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; v3.7.4,     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.

    CVE-2019-9948:
    urllib in Python 2.x through 2.7.16 supports the local_file: scheme, which makes it easier for remote     attackers to bypass protection mechanisms that blacklist file: URIs, as demonstrated by triggering a     urllib.urlopen('local_file:///etc/passwd') call.

    CVE-2020-14422:
    Lib/ipaddress.py in Python through 3.8.3 improperly computes hash values in the IPv4Interface and     IPv6Interface classes, which might allow a remote attacker to cause a denial of service if an application     is affected by the performance of a dictionary containing IPv4Interface or IPv6Interface objects, and this     attacker can cause many dictionary entries to be created. This is fixed in: v3.5.10, v3.5.10rc1; v3.6.12;
    v3.7.9; v3.8.4, v3.8.4rc1, v3.8.5, v3.8.6, v3.8.6rc1; v3.9.0, v3.9.0b4, v3.9.0b5, v3.9.0rc1, v3.9.0rc2.

    CVE-2020-26116:
    http.client in Python 3.x before 3.5.10, 3.6.x before 3.6.12, 3.7.x before 3.7.9, and 3.8.x before 3.8.5     allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR     and LF control characters in the first argument of HTTPConnection.request.

    CVE-2020-27619:
    In Python 3 through 3.9.0, the Lib/test/multibytecodec_support.py CJK codec tests call eval() on content     retrieved via HTTP.

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

    CVE-2021-23336:
    The package python/cpython from 0 and before 3.6.13, from 3.7.0 and before 3.7.10, from 3.8.0 and before     3.8.8, from 3.9.0 and before 3.9.2 are vulnerable to Web Cache Poisoning via urllib.parse.parse_qsl and     urllib.parse.parse_qs by using a vector called parameter cloaking. When the attacker can separate query     parameters using a semicolon (;), they can cause a difference in the interpretation of the request between     the proxy (running with default configuration) and the server. This can result in malicious requests being     cached as completely safe ones, as the proxy would usually not see the semicolon as a separator, and     therefore would not include it in a cache key of an unkeyed parameter.

    CVE-2021-3177:
    Python 3.x through 3.9.1 has a buffer overflow in PyCArg_repr in _ctypes/callproc.c, which may lead to     remote code execution in certain Python applications that accept floating-point numbers as untrusted     input, as demonstrated by a 1e300 argument to c_double.from_param. This occurs because sprintf is used     unsafely.

    CVE-2021-3733:
    ** RESERVED ** This candidate has been reserved by an organization or individual that will use it when     announcing a new security problem. When the candidate has been publicized, the details for this candidate     will be provided.

Tenable has extracted the preceding description block directly from the Alibaba Cloud Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Published	Updated	Severity
138921	Fedora 32 : python27 (2020-e9251de272)	Nessus	Fedora Local Security Checks	7/27/2020	2/19/2021	high
139215	Fedora 31 : python39 (2020-aab24d3714)	Nessus	Fedora Local Security Checks	7/31/2020	2/19/2021	high
139527	Fedora 31 : python36 (2020-efb908b6a8)	Nessus	Fedora Local Security Checks	8/12/2020	2/26/2024	high
294695	MiracleLinux 8 : python3-3.6.8-31.el8 (AXSA:2021-1204:01)	Nessus	Miracle Linux Local Security Checks	1/20/2026	1/20/2026	medium
234998	Amazon Linux AMI : python26 (ALAS-2025-1972)	Nessus	Amazon Linux Local Security Checks	4/30/2025	4/30/2025	medium
236495	Alibaba Cloud Linux 3 : 0080: python3 (ALINUX3-SA-2021:0080)	Nessus	Alibaba Cloud Linux Local Security Checks	5/14/2025	5/14/2025	critical

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