Technology · PyPI
urllib3 (PyPI) vulnerabilities
Updated . Rebuilt every hour.
Junglewise Threat Intelligence has tracked 25 vulnerabilities in urllib3 (PyPI): 0 in the last 7 days and 3 in the last 90 days, 0 of them critical and 0 exploited in the wild. The most recent, CVE-2026-97689, was published on 29 September 2026. Nothing in the last four weeks, down from 3 vulnerabilities in the four before.
- Last 7 days
- 0
- Last 90 days
- 3
- Critical, all time
- 0
- Exploited in the wild
- 0
About urllib3 (PyPI)
Python HTTP client library for making requests and handling connections.
Latest urllib3 (PyPI) vulnerabilities
- CVE-2026-97689: urllib3 HTTP client unbounded memory allocation in chunked transferhighCVSS 4EPSS 0.3%
- CVE-2026-97688: urllib3 infinite loop in Deflate decodermediumCVSS 4EPSS 0.3%
- CVE-2026-97687: urllib3 HTTPS proxy TLS settings isolationhighCVSS 4EPSS 0.2%
- CVE-2025-50182: PYSEC-2026-1997 - urllib3 does not control redirects in browsers and Node.jslowCVSS 3.1EPSS 0.4%
- CVE-2025-50181: PYSEC-2026-1999 - urllib3 redirects are not disabled when retries are disabled on PoolManager instantiationlowCVSS 3.1EPSS 0.5%
- CVE-2024-37891: PYSEC-2026-1995 - urllib3's Proxy-Authorization request header isn't stripped during cross-origin redirectslowCVSS 3.1EPSS 1.1%
- CVE-2026-9375: urllib3 denial of service via Brotli decompression bomb bypasshighCVSS 7.5
- CVE-2026-44432: urllib3 resource exhaustion via improper handling of compressed datahighCVSS 7.5EPSS 0.9%
- CVE-2026-44431: urllib3 sensitive header leak in ProxyManager low-level redirectsmediumCVSS 5.3EPSS 0.3%
- CVE-2026-21441: Python urllib3 denial of service via decompression bomb in redirectshighCVSS 7.5EPSS 3.0%
- CVE-2025-66471: urllib3 streaming API improper compression handlinghighCVSS 7.5EPSS 0.7%
- CVE-2025-66418: PYSEC-2026-1998 - urllib3 allows an unbounded number of links in the decompression chainhighCVSS 7.5EPSS 0.7%
- CVE-2023-45803: urllib3's request body not stripped after redirect from 303 status changes request method to GETlowCVSS 3.1EPSS 0.5%
- CVE-2018-25091: Authorization Header forwarded on redirectlowCVSS 3.1EPSS 0.5%
- CVE-2023-43804: `Cookie` HTTP header isn't stripped on cross-origin redirectslowCVSS 3.1EPSS 1.2%
- CVE-2021-33503: urllib3 ReDoS in URL authority parserhighCVSS 7.5EPSS 3.3%
- CVE-2021-28363: Using default SSLContext for HTTPS requests in an HTTPS proxy doesn't verify certificate hostname for proxy connectionlowCVSS 3.1EPSS 2.1%
- CVE-2020-26137: CRLF injection in urllib3lowCVSS 3.1EPSS 2.3%
- CVE-2020-7212: Uncontrolled Resource Consumption in urllib3lowCVSS 3.1EPSS 3.4%
- CVE-2019-11324: Improper Certificate Validation in urllib3lowCVSS 3EPSS 2.8%
- PYSEC-2019-63 - The urllib3 library before 1.24.2 for Python mishandles certain cases where the desired set of CA…info
- PYSEC-2019-62 - In the urllib3 library through 1.24.1 for Python, CRLF injection is possible if the attacker controls the request parameter.info
- CVE-2019-11236: PYSEC-2019-132 - In the urllib3 library through 1.24.1 for Python, CRLF injection is possible if the attacker controls the…lowCVSS 3EPSS 2.1%
- CVE-2018-20060: Exposure of Sensitive Information to an Unauthorized Actor in urllib3lowCVSS 3EPSS 4.5%
- CVE-2016-9015: Urllib3 Incorrect Certificate ValidationlowCVSS 3EPSS 0.8%
Most severe urllib3 (PyPI) vulnerabilities
Exploited in the wild first, then by severity and CVSS score.
- CVE-2021-33503: urllib3 ReDoS in URL authority parserhighCVSS 7.5EPSS 3.3%
- CVE-2026-21441: Python urllib3 denial of service via decompression bomb in redirectshighCVSS 7.5EPSS 3.0%
- CVE-2026-44432: urllib3 resource exhaustion via improper handling of compressed datahighCVSS 7.5EPSS 0.9%
- CVE-2025-66471: urllib3 streaming API improper compression handlinghighCVSS 7.5EPSS 0.7%
- CVE-2025-66418: PYSEC-2026-1998 - urllib3 allows an unbounded number of links in the decompression chainhighCVSS 7.5EPSS 0.7%
- CVE-2026-9375: urllib3 denial of service via Brotli decompression bomb bypasshighCVSS 7.5
- CVE-2026-97689: urllib3 HTTP client unbounded memory allocation in chunked transferhighCVSS 4EPSS 0.3%
- CVE-2026-97687: urllib3 HTTPS proxy TLS settings isolationhighCVSS 4EPSS 0.2%
- CVE-2026-44431: urllib3 sensitive header leak in ProxyManager low-level redirectsmediumCVSS 5.3EPSS 0.3%
- CVE-2026-97688: urllib3 infinite loop in Deflate decodermediumCVSS 4EPSS 0.3%
Vulnerabilities per week
Nothing in the last four weeks, down from 3 vulnerabilities in the four before. The last 13 weeks, by the week each vulnerability was published.
| Week of | Bar | Vulns | Critical |
|---|---|---|---|
| 17 Aug 2026 | 0 | 0 | |
| 24 Aug 2026 | 0 | 0 | |
| 31 Aug 2026 | 0 | 0 | |
| 7 Sep 2026 | 0 | 0 | |
| 14 Sep 2026 | 0 | 0 | |
| 21 Sep 2026 | 0 | 0 | |
| 28 Sep 2026 | 3 | 0 | |
| 5 Oct 2026 | 0 | 0 | |
| 12 Oct 2026 | 0 | 0 | |
| 19 Oct 2026 | 0 | 0 | |
| 26 Oct 2026 | 0 | 0 | |
| 2 Nov 2026 | 0 | 0 | |
| 9 Nov 2026 | 0 | 0 |
Embed a badge
A live badge for a README, a status page or an internal wiki: how many urllib3 (PyPI) vulnerabilities were published in the last 7 days and how many of them are critical, refreshed hourly.
[](https://junglewise.ai/threats/technologies/urllib3)<a href="https://junglewise.ai/threats/technologies/urllib3"><img src="https://junglewise.ai/threats/technologies/urllib3/badge.svg" alt="urllib3 (PyPI) vulnerabilities" /></a>How this is built
Junglewise Threat Intelligence collects vulnerabilities from NVD, GitHub Security Advisories, OSV, the CISA Known Exploited Vulnerabilities catalog, FIRST EPSS and vendor advisories, and matches each one to the technologies and vendors it affects. Dates are the date a vulnerability was published, in UTC.
The pages are rebuilt from the database every hour. Frozen weekly and monthly reports never change once published, so they can be cited.
Use this data
The same data is at https://junglewise.ai/threats/technologies/urllib3.json, and this page as text at https://junglewise.ai/threats/technologies/urllib3.md, for scripts and language models. It is free to reuse under CC BY 4.0 with a link back to this page.
Cite as: Junglewise Threat Intelligence, "urllib3 (PyPI) vulnerabilities", https://junglewise.ai/threats/technologies/urllib3, 13 November 2026.