Vulnerability in Python

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."

EPSS: 0.148 (96.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N.

Affected products

  • Python — versions 3.5.0, 3.5.1, 3.0
  • N/a — versions n/a

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2016-0772?
CVE-2016-0772 is a medium-severity vulnerability in Python, classified under Protection Mechanism Failure. CVSS score: 6.5/10. Published 2016-09-02.
How severe is CVE-2016-0772?
Medium severity. CVSS v3 base score is 6.5 out of 10.
Is CVE-2016-0772 known to be exploited?
5 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.