UpHeron
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Servers and applications

CVE-2016-0772

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."

Severity
Medium 6.5
Published
2 Sept 2016
Last changed
17 Jun 2026
Added to UpHeron
21 Oct 2026
Sources
NVD

Affected software

SoftwareAffected versions
PythonServers and applications · cpe:a:python:python
  • Version 3.5.1
  • Version 3.5.0
  • Version 3.4.4
  • Version 3.4.3
All 30 release lines
  • Every version up to 2.7.11
  • Version 3.0
  • Version 3.0.1
  • Version 3.1.0
  • Version 3.1.1
  • Version 3.1.2
  • Version 3.1.3
  • Version 3.1.4
  • Version 3.1.5
  • Version 3.2.0
  • Version 3.2.1
  • Version 3.2.2
  • Version 3.2.3
  • Version 3.2.4
  • Version 3.2.5
  • Version 3.2.6
  • Version 3.3.0
  • Version 3.3.1
  • Version 3.3.2
  • Version 3.3.3
  • Version 3.3.4
  • Version 3.3.5
  • Version 3.3.6
  • Version 3.4.0
  • Version 3.4.1
  • Version 3.4.2
  • Version 3.4.3
  • Version 3.4.4
  • Version 3.5.0
  • Version 3.5.1

References

  • NVD https://nvd.nist.gov/vuln/detail/CVE-2016-0772
  • CVE.org https://www.cve.org/CVERecord?id=CVE-2016-0772