python: smtplib StartTLS stripping attack
Published Sep 2, 2016
6.5
MEDIUMCVSS 3.0
EPSS 14.52%
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."
Affected products
No data.
Configuration 2
- 3.0
- 3.0.1
- 3.1.0
- 3.1.1
- 3.1.2
- 3.1.3
- 3.1.4
- 3.1.5
- 3.2.0
- 3.2.1
- 3.2.2
- 3.2.3
- 3.2.4
- 3.2.5
- 3.2.6
- 3.3.0
- 3.3.1
- 3.3.2
- 3.3.3
- 3.3.4
- 3.3.5
- 3.3.6
- 3.4.0
- 3.4.1
- 3.4.2
- 3.4.3
- 3.4.4
No data.
Red Hat Enterprise Linux 6
python-0:2.6.6-66.el6_8
Fixed · RHSA-2016:1626
Red Hat Enterprise Linux 7
python-0:2.7.5-38.el7_2
Fixed · RHSA-2016:1626
Red Hat Software Collections for Red Hat Enterprise Linux 6
python27-python-0:2.7.8-18.el6
Fixed · RHSA-2016:1628
Red Hat Software Collections for Red Hat Enterprise Linux 6
python33-python-0:3.3.2-18.el6
Fixed · RHSA-2016:1629
Red Hat Software Collections for Red Hat Enterprise Linux 6
rh-python34-python-0:3.4.2-14.el6
Fixed · RHSA-2016:1630
Red Hat Software Collections for Red Hat Enterprise Linux 6.6 EUS
python27-python-0:2.7.8-18.el6
Fixed · RHSA-2016:1628
Red Hat Software Collections for Red Hat Enterprise Linux 6.6 EUS
python33-python-0:3.3.2-18.el6
Fixed · RHSA-2016:1629
Red Hat Software Collections for Red Hat Enterprise Linux 6.6 EUS
rh-python34-python-0:3.4.2-14.el6
Fixed · RHSA-2016:1630
Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUS
python27-python-0:2.7.8-18.el6
Fixed · RHSA-2016:1628
Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUS
python33-python-0:3.3.2-18.el6
Fixed · RHSA-2016:1629
Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUS
rh-python34-python-0:3.4.2-14.el6
Fixed · RHSA-2016:1630
Red Hat Software Collections for Red Hat Enterprise Linux 7
python27-python-0:2.7.8-16.el7
Fixed · RHSA-2016:1628
Red Hat Software Collections for Red Hat Enterprise Linux 7
python33-python-0:3.3.2-16.el7
Fixed · RHSA-2016:1629
Red Hat Software Collections for Red Hat Enterprise Linux 7
rh-python34-python-0:3.4.2-13.el7
Fixed · RHSA-2016:1630
Red Hat Software Collections for Red Hat Enterprise Linux 7
rh-python35-python-0:3.5.1-9.el7
Fixed · RHSA-2016:1627
Red Hat Software Collections for Red Hat Enterprise Linux 7.1 EUS
python27-python-0:2.7.8-16.el7
Fixed · RHSA-2016:1628
Red Hat Software Collections for Red Hat Enterprise Linux 7.1 EUS
python33-python-0:3.3.2-16.el7
Fixed · RHSA-2016:1629
Red Hat Software Collections for Red Hat Enterprise Linux 7.1 EUS
rh-python34-python-0:3.4.2-13.el7
Fixed · RHSA-2016:1630
Red Hat Software Collections for Red Hat Enterprise Linux 7.1 EUS
rh-python35-python-0:3.5.1-9.el7
Fixed · RHSA-2016:1627
Red Hat Software Collections for Red Hat Enterprise Linux 7.2 EUS
python27-python-0:2.7.8-16.el7
Fixed · RHSA-2016:1628
Red Hat Software Collections for Red Hat Enterprise Linux 7.2 EUS
python33-python-0:3.3.2-16.el7
Fixed · RHSA-2016:1629
Red Hat Software Collections for Red Hat Enterprise Linux 7.2 EUS
rh-python34-python-0:3.4.2-13.el7
Fixed · RHSA-2016:1630
Red Hat Software Collections for Red Hat Enterprise Linux 7.2 EUS
rh-python35-python-0:3.5.1-9.el7
Fixed · RHSA-2016:1627
Red Hat Enterprise Linux 5
python
Will not fix
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 6 | python-0:2.6.6-66.el6_8 | Fixed | RHSA-2016:1626 |
| Red Hat Enterprise Linux 7 | python-0:2.7.5-38.el7_2 | Fixed | RHSA-2016:1626 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | python27-python-0:2.7.8-18.el6 | Fixed | RHSA-2016:1628 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | python33-python-0:3.3.2-18.el6 | Fixed | RHSA-2016:1629 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | rh-python34-python-0:3.4.2-14.el6 | Fixed | RHSA-2016:1630 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6.6 EUS | python27-python-0:2.7.8-18.el6 | Fixed | RHSA-2016:1628 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6.6 EUS | python33-python-0:3.3.2-18.el6 | Fixed | RHSA-2016:1629 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6.6 EUS | rh-python34-python-0:3.4.2-14.el6 | Fixed | RHSA-2016:1630 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUS | python27-python-0:2.7.8-18.el6 | Fixed | RHSA-2016:1628 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUS | python33-python-0:3.3.2-18.el6 | Fixed | RHSA-2016:1629 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUS | rh-python34-python-0:3.4.2-14.el6 | Fixed | RHSA-2016:1630 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | python27-python-0:2.7.8-16.el7 | Fixed | RHSA-2016:1628 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | python33-python-0:3.3.2-16.el7 | Fixed | RHSA-2016:1629 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | rh-python34-python-0:3.4.2-13.el7 | Fixed | RHSA-2016:1630 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | rh-python35-python-0:3.5.1-9.el7 | Fixed | RHSA-2016:1627 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.1 EUS | python27-python-0:2.7.8-16.el7 | Fixed | RHSA-2016:1628 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.1 EUS | python33-python-0:3.3.2-16.el7 | Fixed | RHSA-2016:1629 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.1 EUS | rh-python34-python-0:3.4.2-13.el7 | Fixed | RHSA-2016:1630 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.1 EUS | rh-python35-python-0:3.5.1-9.el7 | Fixed | RHSA-2016:1627 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.2 EUS | python27-python-0:2.7.8-16.el7 | Fixed | RHSA-2016:1628 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.2 EUS | python33-python-0:3.3.2-16.el7 | Fixed | RHSA-2016:1629 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.2 EUS | rh-python34-python-0:3.4.2-13.el7 | Fixed | RHSA-2016:1630 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.2 EUS | rh-python35-python-0:3.5.1-9.el7 | Fixed | RHSA-2016:1627 |
| Red Hat Enterprise Linux 5 | python | Will not fix | n/a |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N
1 other source (Red Hat) ▾
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
AV:N/AC:M/Au:N/C:P/I:P/A:N
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2022–2026- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (44 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 14.52% (0.14524) | 96.54th | v5 (v2026.06.15) |
| Sep 22, 2026 | 14.52% (0.14524) | 96.48th | v5 (v2026.06.15) |
| Sep 21, 2026 | 16.40% (0.16399) | 96.89th | v5 (v2026.06.15) |
| Sep 6, 2026 | 14.52% (0.14524) | 96.40th | v5 (v2026.06.15) |
| Sep 5, 2026 | 16.40% (0.16399) | 96.82th | v5 (v2026.06.15) |
| Aug 30, 2026 | 14.52% (0.14524) | 96.38th | v5 (v2026.06.15) |
| Aug 28, 2026 | 16.40% (0.16399) | 96.80th | v5 (v2026.06.15) |
| Aug 24, 2026 | 14.52% (0.14524) | 96.36th | v5 (v2026.06.15) |
| Aug 23, 2026 | 16.40% (0.16399) | 96.79th | v5 (v2026.06.15) |
| Jun 15, 2026 | 14.52% (0.14524) | 96.19th | v5 (v2026.06.15) |
| May 1, 2026 | 7.64% (0.07644) | 91.90th | v4 (v2025.03.14) |
| Mar 4, 2026 | 5.78% (0.05778) | 90.32th | v4 (v2025.03.14) |
| Mar 1, 2026 | 7.51% (0.07511) | 91.68th | v4 (v2025.03.14) |
| Feb 4, 2026 | 5.78% (0.05778) | 90.26th | v4 (v2025.03.14) |
| Feb 1, 2026 | 7.51% (0.07511) | 91.62th | v4 (v2025.03.14) |
| Jan 4, 2026 | 5.78% (0.05778) | 90.19th | v4 (v2025.03.14) |
| Jan 1, 2026 | 7.51% (0.07511) | 91.56th | v4 (v2025.03.14) |
| Dec 18, 2025 | 5.78% (0.05778) | 90.16th | v4 (v2025.03.14) |
| Dec 14, 2025 | 4.47% (0.04469) | 88.68th | v4 (v2025.03.14) |
| Dec 4, 2025 | 5.95% (0.05947) | 90.28th | v4 (v2025.03.14) |
| Dec 1, 2025 | 7.72% (0.07725) | 91.63th | v4 (v2025.03.14) |
| Oct 28, 2025 | 13.18% (0.13176) | 93.81th | v4 (v2025.03.14) |
| Oct 27, 2025 | 11.06% (0.11062) | 93.15th | v4 (v2025.03.14) |
| Oct 1, 2025 | 14.12% (0.14116) | 94.16th | v4 (v2025.03.14) |
| Sep 15, 2025 | 11.06% (0.11062) | 93.19th | v4 (v2025.03.14) |
| Sep 4, 2025 | 6.98% (0.06978) | 91.10th | v4 (v2025.03.14) |
| Sep 1, 2025 | 8.89% (0.08895) | 92.28th | v4 (v2025.03.14) |
| Aug 20, 2025 | 6.98% (0.06978) | 91.05th | v4 (v2025.03.14) |
| Aug 18, 2025 | 11.06% (0.11062) | 93.16th | v4 (v2025.03.14) |
| Aug 4, 2025 | 6.98% (0.06978) | 91.05th | v4 (v2025.03.14) |
| Aug 1, 2025 | 8.89% (0.08895) | 92.25th | v4 (v2025.03.14) |
| Jul 12, 2025 | 6.56% (0.06561) | 90.70th | v4 (v2025.03.14) |
| Mar 30, 2025 | 10.44% (0.10435) | 92.52th | v4 (v2025.03.14) |
| Mar 29, 2025 | 7.78% (0.07781) | 86.31th | v4 (v2025.03.14) |
| Mar 19, 2025 | 10.44% (0.10435) | 92.27th | v4 (v2025.03.14) |
| Mar 17, 2025 | 7.96% (0.07963) | 91.45th | v4 (v2025.03.14) |
| Dec 12, 2024 | 1.63% (0.01634) | 88.04th | v3 (v2023.03.01) |
| Mar 17, 2024 | 1.63% (0.01634) | 87.22th | v3 (v2023.03.01) |
| Feb 13, 2024 | 1.24% (0.01239) | 85.03th | v3 (v2023.03.01) |
| Oct 26, 2023 | 0.88% (0.00876) | 80.62th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.62% (0.00619) | 75.53th | v3 (v2023.03.01) |
| Mar 6, 2023 | 18.33% (0.18327) | 96.32th | v2 (v2022.01.01) |
| Apr 1, 2022 | 18.33% (0.18327) | 95.99th | v2 (v2022.01.01) |
| Feb 4, 2022 | 18.33% (0.18327) | 93.57th | v2 (v2022.01.01) |
References (21)
- http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00040.html vendor-advisoryx_refsource_SUSE
- http://rhn.redhat.com/errata/RHSA-2016-1626.html vendor-advisoryx_refsource_REDHAT
- http://rhn.redhat.com/errata/RHSA-2016-1627.html vendor-advisoryx_refsource_REDHAT
- http://rhn.redhat.com/errata/RHSA-2016-1628.html vendor-advisoryx_refsource_REDHAT
- http://rhn.redhat.com/errata/RHSA-2016-1629.html vendor-advisoryx_refsource_REDHAT
- http://rhn.redhat.com/errata/RHSA-2016-1630.html vendor-advisoryx_refsource_REDHAT
- http://www.openwall.com/lists/oss-security/2016/06/14/9 mailing-listx_refsource_MLISTMailing List
- http://www.securityfocus.com/bid/91225 vdb-entryx_refsource_BID
- http://www.splunk.com/view/SP-CAAAPSV x_refsource_CONFIRM
- http://www.splunk.com/view/SP-CAAAPUE x_refsource_CONFIRM
- https://access.redhat.com/security/cve/CVE-2016-0772 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1303647 x_refsource_CONFIRMIssue TrackingThird Party Advisory
- https://docs.python.org/3.4/whatsnew/changelog.html#python-3-4-5 x_refsource_CONFIRMRelease Notes
- https://docs.python.org/3.5/whatsnew/changelog.html#python-3-5-2 x_refsource_CONFIRMRelease Notes
- https://hg.python.org/cpython/raw-file/v2.7.12/Misc/NEWS x_refsource_CONFIRMRelease Notes
- https://hg.python.org/cpython/rev/b3ce713fb9be x_refsource_CONFIRMPatch
- https://hg.python.org/cpython/rev/d590114c2394 x_refsource_CONFIRMPatch
- https://lists.debian.org/debian-lts-announce/2019/02/msg00011.html mailing-listx_refsource_MLIST
- https://nvd.nist.gov/vuln/detail/CVE-2016-0772
- https://security.gentoo.org/glsa/201701-18 vendor-advisoryx_refsource_GENTOO
- https://www.cve.org/CVERecord?id=CVE-2016-0772
Change history (0)
No recorded changes yet.