The smtplib library in CPython (aka Python) before 2.7.12, 3.x before 3.4.5, and 3.5.x before 3.5.2 does not return an error when StartTLS fails, which might allow man-in-the-middle attackers to bypass the TLS protections by leveraging a network position between the client and the registry to block the StartTLS command, aka a "StartTLS stripping attack."

The smtplib library in CPython (aka Python) before 2.7.12, 3.x before 3.4.5, and 3.5.x before 3.5.2 does not return an error when StartTLS fails, which might allow man-in-the-middle attackers to bypass the TLS protections by leveraging a network position between the client and the registry to block the StartTLS command, aka a "StartTLS stripping attack."

Security update for python3

python: smtplib StartTLS stripping attack python: http protocol steam injection attack CGIHandler: sets environmental variable based on user supplied Proxy request header

Security update for python

Affected: Ubuntu:14.04:LTS: python2.7, Ubuntu:14.04:LTS: python3.4, Ubuntu:14.04:LTS: python3.5, Ubuntu:16.04:LTS: python2.7, Ubuntu:16.04:LTS: python3.5

The smtplib library in CPython (aka Python) before 2.7.12, 3.x before 3.4.5, and 3.5.x before 3.5.2 does not return an error when StartTLS fails, which might allow man-in-the-middle attackers to bypass the TLS protections by leveraging a network position between the client and the registry to block the StartTLS command, aka a "StartTLS stripping attack."