CVE-2016-9015
Versions 1.17 and 1.18 of the Python urllib3 library suffer from a vulnerability that can cause them, in certain configurations, to not…
- Published
- Updated
- Reserved
- Assigned by
- mitre
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.
Timeline
ID reserved
By mitre
- 3 months later
· 3 months later
Published
- 8 years later
· 8 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.0 | Low3.7 | CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N |
- EPSS (exploitation in 30 days)
- 0.75% · top 45% of all CVEs (8 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Low 3.7.
Weakness
Affected products
n/a
- affected n/a
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- PyPIurllib3GHSA-v4w5-p2hg-8fh6 (opens in a new tab)
References (2)
- 93941 (opens in a new tab)vdb-entryx_refsource_BIDx_transferred
- [oss-security] 20161027 CVE-2016-9015: Python urllib3 1.17 and 1.18 certificate verification failure (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-v4w5-p2hg-8fh6 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2016-9015)Record last updated .