VULNERABILITY INTELLIGENCE

CVE-2016-0772

CVSS score6.5 MEDIUM
EPSS probability14.52%
CISA KEVNot currently listed
Published2016-09-02
Last modified2026-06-17
CVSS vectorCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N

Description

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."

Weakness classification

  • CWE-693: Protection Mechanism Failure

Primary references