CVE-2016-0772
MEDIUMEPSS 96th pctlDescription
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."
CVSS v3 Vector
Exploitability
Impact
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N
Exploit Intelligence
Very high risk: more likely to be exploited than 96% of all known CVEs.
References
- http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00040.html
- http://rhn.redhat.com/errata/RHSA-2016-1626.html
- http://rhn.redhat.com/errata/RHSA-2016-1627.html
- http://rhn.redhat.com/errata/RHSA-2016-1628.html
- http://rhn.redhat.com/errata/RHSA-2016-1629.html
- http://rhn.redhat.com/errata/RHSA-2016-1630.html
- http://www.openwall.com/lists/oss-security/2016/06/14/9
- http://www.securityfocus.com/bid/91225
- http://www.splunk.com/view/SP-CAAAPSV
- http://www.splunk.com/view/SP-CAAAPUE
- https://bugzilla.redhat.com/show_bug.cgi?id=1303647
- https://docs.python.org/3.4/whatsnew/changelog.html#python-3-4-5
- https://docs.python.org/3.5/whatsnew/changelog.html#python-3-5-2
- https://hg.python.org/cpython/raw-file/v2.7.12/Misc/NEWS
- https://hg.python.org/cpython/rev/b3ce713fb9be
- https://hg.python.org/cpython/rev/d590114c2394
- https://lists.debian.org/debian-lts-announce/2019/02/msg00011.html
- https://security.gentoo.org/glsa/201701-18
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Start freeThis product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-06.