urllib3 — CVE history (PyPI)
urllib3
19 CVEs affect the urllib3 PyPI package (highest CVSS 9.8). Latest disclosed: 2026-05-13. Full CVE history sourced from NVD.
Summary
- Package
urllib3(PyPI)- Total CVEs
19- Actively exploited (CISA KEV)
- 0
- Highest CVSS
9.8- Latest disclosed
- 2026-05-13
Recent CVEs (top 19)
| CVE | Severity | CVSS | KEV | Published | Summary |
|---|---|---|---|---|---|
CVE-2026-44432 | High | 7.5 | — | 2026-05-13 | urllib3 is an HTTP client library for Python. |
CVE-2026-44431 | Medium | 5.3 | — | 2026-05-13 | urllib3 is an HTTP client library for Python. |
CVE-2026-21441 | High | 7.5 | — | 2026-01-07 | urllib3 is an HTTP client library for Python. |
CVE-2025-66471 | High | 7.5 | — | 2025-12-05 | urllib3 is a user-friendly HTTP client library for Python. |
CVE-2025-66418 | High | 7.5 | — | 2025-12-05 | urllib3 is a user-friendly HTTP client library for Python. |
CVE-2025-50182 | Medium | 5.3 | — | 2025-06-19 | urllib3 is a user-friendly HTTP client library for Python. |
CVE-2025-50181 | Medium | 5.3 | — | 2025-06-19 | urllib3 is a user-friendly HTTP client library for Python. |
CVE-2024-37891 | Medium | 4.4 | — | 2024-06-17 | urllib3 is a user-friendly HTTP client library for Python. |
CVE-2023-45803 | Medium | 4.2 | — | 2023-10-17 | urllib3 is a user-friendly HTTP client library for Python. |
CVE-2018-25091 | Medium | 6.1 | — | 2023-10-15 | urllib3 before 1.24.2 does not remove the authorization HTTP header when following a cross-origin redirect (i.e., a redirect that differs in host, port, or scheme). |
CVE-2023-43804 | Medium | 5.9 | — | 2023-10-04 | urllib3 is a user-friendly HTTP client library for Python. |
CVE-2021-33503 | High | 7.5 | — | 2021-06-29 | An issue was discovered in urllib3 before 1.26.5. |
CVE-2021-28363 | Medium | 6.5 | — | 2021-03-15 | The urllib3 library 1.26.x before 1.26.4 for Python omits SSL certificate validation in some cases involving HTTPS to HTTPS proxies. |
CVE-2020-26137 | Medium | 6.5 | — | 2020-09-30 | urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). |
CVE-2020-7212 | High | 7.5 | — | 2020-03-06 | The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denial of service (CPU consumption) because of an inefficient algorithm. |
CVE-2019-11324 | High | 7.5 | — | 2019-04-18 | The urllib3 library before 1.24.2 for Python mishandles certain cases where the desired set of CA certificates is different from the OS store of CA certificates, which results in SSL connections succeeding in situations where a verificatio… |
CVE-2019-11236 | Medium | 6.1 | — | 2019-04-15 | In the urllib3 library through 1.24.1 for Python, CRLF injection is possible if the attacker controls the request parameter. |
CVE-2018-20060 | Critical | 9.8 | — | 2018-12-11 | urllib3 before version 1.23 does not remove the Authorization HTTP header when following a cross-origin redirect (i.e., a redirect that differs in host, port, or scheme). |
CVE-2016-9015 | Low | 3.7 | — | 2017-01-11 | 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. |
All-time worst (top 10 by CVSS)
| CVE | Severity | CVSS | KEV | Published | Summary |
|---|---|---|---|---|---|
CVE-2018-20060 | Critical | 9.8 | — | 2018-12-11 | urllib3 before version 1.23 does not remove the Authorization HTTP header when following a cross-origin redirect (i.e., a redirect that differs in host, port, or scheme). |
CVE-2026-44432 | High | 7.5 | — | 2026-05-13 | urllib3 is an HTTP client library for Python. |
CVE-2026-21441 | High | 7.5 | — | 2026-01-07 | urllib3 is an HTTP client library for Python. |
CVE-2025-66471 | High | 7.5 | — | 2025-12-05 | urllib3 is a user-friendly HTTP client library for Python. |
CVE-2025-66418 | High | 7.5 | — | 2025-12-05 | urllib3 is a user-friendly HTTP client library for Python. |
CVE-2021-33503 | High | 7.5 | — | 2021-06-29 | An issue was discovered in urllib3 before 1.26.5. |
CVE-2020-7212 | High | 7.5 | — | 2020-03-06 | The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denial of service (CPU consumption) because of an inefficient algorithm. |
CVE-2019-11324 | High | 7.5 | — | 2019-04-18 | The urllib3 library before 1.24.2 for Python mishandles certain cases where the desired set of CA certificates is different from the OS store of CA certificates, which results in SSL connections succeeding in situations where a verificatio… |
CVE-2021-28363 | Medium | 6.5 | — | 2021-03-15 | The urllib3 library 1.26.x before 1.26.4 for Python omits SSL certificate validation in some cases involving HTTPS to HTTPS proxies. |
CVE-2020-26137 | Medium | 6.5 | — | 2020-09-30 | urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). |