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 application.
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 3.5.3-1+deb9u2.
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: https://security-tracker.debian.org/tracker/python3.5
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