Hash: SHA256

             AUSCERT External Security Bulletin Redistribution

                         python3.5 security update
                               16 July 2020


        AusCERT Security Bulletin Summary

Product:           python3.5
Publisher:         Debian
Operating System:  Debian GNU/Linux 9
Impact/Access:     Denial of Service        -- Remote/Unauthenticated      
                   Cross-site Scripting     -- Remote with User Interaction
                   Access Confidential Data -- Remote/Unauthenticated      
                   Unauthorised Access      -- Remote/Unauthenticated      
                   Reduced Security         -- Remote/Unauthenticated      
Resolution:        Patch/Upgrade
CVE Names:         CVE-2020-14422 CVE-2020-8492 CVE-2019-18348
                   CVE-2019-16935 CVE-2019-16056 CVE-2019-11340
                   CVE-2019-10160 CVE-2019-9948 CVE-2019-9947
                   CVE-2019-9740 CVE-2019-9636 CVE-2019-5010
                   CVE-2018-20852 CVE-2018-20406 

Reference:         ASB-2020.0129

Original Bulletin: 

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Debian LTS Advisory DLA-2280-1                debian-lts@lists.debian.org
July 15, 2020                                 https://wiki.debian.org/LTS
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Package        : python3.5
Version        : 3.5.3-1+deb9u2
CVE ID         : CVE-2018-20406 CVE-2018-20852 CVE-2019-5010 CVE-2019-9636
                 CVE-2019-9740 CVE-2019-9947 CVE-2019-9948 CVE-2019-10160
                 CVE-2019-16056 CVE-2019-16935 CVE-2019-18348 CVE-2020-8492
Debian Bug     : 924072 921064 940901

Multiple security issues were discovered in Python, an interactive
high-level object-oriented language.


    Modules/_pickle.c has an integer overflow via a large LONG_BINPUT
    value that is mishandled during a "resize to twice the size"
    attempt. This issue might cause memory exhaustion, but is only
    relevant if the pickle format is used for serializing tens or
    hundreds of gigabytes of data.


    http.cookiejar.DefaultPolicy.domain_return_ok in
    Lib/http/cookiejar.py does not correctly validate the domain: it
    can be tricked into sending existing cookies to the wrong
    server. An attacker may abuse this flaw by using a server with a
    hostname that has another valid hostname as a suffix (e.g.,
    pythonicexample.com to steal cookies for example.com). When a
    program uses http.cookiejar.DefaultPolicy and tries to do an HTTP
    connection to an attacker-controlled server, existing cookies can
    be leaked to the attacker.


    An exploitable denial-of-service vulnerability exists in the X509
    certificate parser. 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.


    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.


    An issue was discovered in urllib2. 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 query string after a ? character) followed by an HTTP
    header or a Redis command.


    An issue was discovered in urllib2. 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.


    urllib 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.


    A security regression was discovered in python, 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


    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.


    The documentation XML-RPC server has XSS via the server_title
    field. This occurs in Lib/xmlrpc/server.py. If set_server_title is
    called with untrusted input, arbitrary JavaScript can be delivered
    to clients that visit the http URL for this server.


    An issue was discovered in urllib2. 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 host component of a URL) followed by an HTTP header. This
    is similar to the CVE-2019-9740 query string issue and the
    CVE-2019-9947 path string issue


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


    Lib/ipaddress.py 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.

For Debian 9 stretch, these problems have been fixed in version

We recommend that you upgrade your python3.5 packages.

For the detailed security status of python3.5 please refer to
its security tracker page at:

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS


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