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
02 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
03 Exploitation and scoring
- Exploitation
- Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
- SSVC decision
- Not assessed by CISA
- EPSS probability
- 15.35% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 96.7% of scored records. A rank, not a probability.
- NVD base score
- 6.5 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N
- NVD analysis status
- Modified. NVD last modified this record on 2026-06-17.
- Red Hat severity
- Moderate. Red Hat's rating for its own products, not a CVSS rating.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2016-09-02 14:00Z10 YR AGO
- Last updated
- 2024-08-05 22:30Z2 YR AGO
- Reserved
- 2015-12-16
- Assigning CNA
- redhat
- Record state
- PUBLISHED
- Severity
- Not rated by the issuing CNA
- CNA CVSS vector
- Not published by the issuing CNA
- Weaknesses
- CWE-693Protection Mechanism FailurePillar
- Data version
- 5.1
- Document digest
- 749befe6e645c92555281660729b8fd8cdb6df77d5a67d196c4f5b09d9751b14
05 Affected products
06 References
- hg.python.orghttps://hg.python.org/cpython/rev/d590114c2394
- www.splunk.comhttp://www.splunk.com/view/SP-CAAAPUE
- rhn.redhat.comRHSA-2016:1630http://rhn.redhat.com/errata/RHSA-2016-1630.html
- rhn.redhat.comRHSA-2016:1627http://rhn.redhat.com/errata/RHSA-2016-1627.html
- hg.python.orghttps://hg.python.org/cpython/rev/b3ce713fb9be
- rhn.redhat.comRHSA-2016:1629http://rhn.redhat.com/errata/RHSA-2016-1629.html
- www.splunk.comhttp://www.splunk.com/view/SP-CAAAPSV
- lists.debian.org[debian-lts-announce] 20190207 [SECURITY] [DLA 1663-1] python3.4 security updatehttps://lists.debian.org/debian-lts-announce/2019/02/msg00011.html
- bugzilla.redhat.comhttps://bugzilla.redhat.com/show_bug.cgi?id=1303647
- docs.python.orghttps://docs.python.org/3.4/whatsnew/changelog.html#python-3-4-5
- www.openwall.com[oss-security] 20160614 Python CVE-2016-0772: smtplib StartTLS stripping attackhttp://www.openwall.com/lists/oss-security/2016/06/14/9
- hg.python.orghttps://hg.python.org/cpython/raw-file/v2.7.12/Misc/NEWS
- security.gentoo.orgGLSA-201701-18https://security.gentoo.org/glsa/201701-18
- docs.python.orghttps://docs.python.org/3.5/whatsnew/changelog.html#python-3-5-2
- www.securityfocus.com91225http://www.securityfocus.com/bid/91225
- rhn.redhat.comRHSA-2016:1628http://rhn.redhat.com/errata/RHSA-2016-1628.html
- rhn.redhat.comRHSA-2016:1626http://rhn.redhat.com/errata/RHSA-2016-1626.html
- lists.opensuse.orgopenSUSE-SU-2020:0086http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00040.html
07 Fixed in
Debian 11
- python2.7 Fixed in 2.7.12~rc1-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 14.04 LTS
- python2.7 Fixed in 2.7.6-8ubuntu0.3
- python3.4 Fixed in 3.4.3-1ubuntu1~14.04.5
- python3.5 Fixed in 3.5.2-2ubuntu0~16.04.4~14.04.1
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 16.04 LTS
- python2.7 Fixed in 2.7.12-1ubuntu0~16.04.1
- python3.5 Fixed in 3.5.2-2ubuntu0~16.04.1
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.