Versions 1.17 and 1.18 of the Python urllib3 library suffer from a vulnerability that can cause them, in certain configurations, to not correctly validate TLS certificates
Published Jan 11, 2017
6.3
MEDIUMCVSS 4.0
EPSS 0.75%
Description
Versions 1.17 and 1.18 of the Python urllib3 library suffer from a vulnerability that can cause them, in certain configurations, to not correctly validate TLS certificates. This places users of the library with those configurations at risk of man-in-the-middle and information leakage attacks. This vulnerability affects users using versions 1.17 and 1.18 of the urllib3 library, who are using the optional PyOpenSSL support for TLS instead of the regular standard library TLS backend, and who are using OpenSSL 1.1.0 via PyOpenSSL. This is an extremely uncommon configuration, so the security impact of this vulnerability is low.
Affected products
Remediation
No remediation recorded yet.
Metrics
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
No CVSS v3.1 score for this CVE.
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
AV:N/AC:H/Au:N/C:P/I:N/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 (10 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 0.75% (0.00754) | 53.38th | v5 (v2026.06.15) |
| Jun 15, 2026 | 0.78% (0.00775) | 50.79th | v5 (v2026.06.15) |
| Mar 17, 2025 | 0.55% (0.00549) | 65.97th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.07% (0.00065) | 30.66th | v3 (v2023.03.01) |
| Jun 14, 2024 | 0.07% (0.00065) | 28.65th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.07% (0.00065) | 26.62th | v3 (v2023.03.01) |
| Mar 6, 2023 | 0.89% (0.00885) | 27.89th | v2 (v2022.01.01) |
| Sep 10, 2022 | 0.89% (0.00885) | 26.24th | v2 (v2022.01.01) |
| Apr 1, 2022 | 0.89% (0.00885) | 24.24th | v2 (v2022.01.01) |
| Feb 4, 2022 | 0.89% (0.00885) | 10.50th | v2 (v2022.01.01) |
References (7)
- http://www.openwall.com/lists/oss-security/2016/10/27/6 mailing-listx_refsource_MLISTMailing ListMitigation
- http://www.securityfocus.com/bid/93941 vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry
- https://github.com/advisories/GHSA-v4w5-p2hg-8fh6 Advisory
- https://github.com/pypa/advisory-database/tree/main/vulns/urllib3/PYSEC-2017-98.yaml
- https://github.com/urllib3/urllib3/commit/c32cdbc16a9634fa0f8c829d1270301570158715
- https://nvd.nist.gov/vuln/detail/CVE-2016-9015
- https://web.archive.org/web/20210123184150/http://www.securityfocus.com/bid/93941
| Link | Providers | Tags |
|---|---|---|
| http://www.openwall.com/lists/oss-security/2016/10/27/6 | mailing-listx_refsource_MLISTMailing ListMitigation | |
| http://www.securityfocus.com/bid/93941 | vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry | |
| https://github.com/advisories/GHSA-v4w5-p2hg-8fh6 | Advisory | |
| https://github.com/pypa/advisory-database/tree/main/vulns/urllib3/PYSEC-2017-98.yaml | ||
| https://github.com/urllib3/urllib3/commit/c32cdbc16a9634fa0f8c829d1270301570158715 | ||
| https://nvd.nist.gov/vuln/detail/CVE-2016-9015 | ||
| https://web.archive.org/web/20210123184150/http://www.securityfocus.com/bid/93941 |
Change history (0)
No recorded changes yet.