# Urllib3 vulnerabilities

Source: https://junglewise.ai/threats/vendors/urllib3  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Updated: 9 November 2026, 03:07 UTC. Rebuilt every hour.  
Data: https://junglewise.ai/threats/vendors/urllib3.json  
License: CC BY 4.0 with a link back

Junglewise Threat Intelligence has tracked 9 vulnerabilities in Urllib3: 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. 1 technology has a page of its own.

## Counts

- Last 7 days: 0
- Last 30 days: 0
- Last 90 days: 3
- All time: 9 (0 critical, 0 exploited in the wild)

## About Urllib3

Python HTTP client library providing utilities for making HTTP requests and managing connections.

## Latest Urllib3 vulnerabilities

- [CVE-2026-97689: urllib3 HTTP client unbounded memory allocation in chunked transfer](https://junglewise.ai/threats/cve-2026-97689-urllib3-is-an-http-client-library-for-python-from-1-10-3-until-2) (high, CVSS 4, published 29 Sep 2026)
- [CVE-2026-97688: urllib3 infinite loop in Deflate decoder](https://junglewise.ai/threats/cve-2026-97688-urllib3-is-an-http-client-library-for-python-from-2-6-2-until-2-8) (medium, CVSS 4, published 29 Sep 2026)
- [CVE-2026-97687: urllib3 HTTPS proxy TLS settings isolation](https://junglewise.ai/threats/cve-2026-97687-urllib3-is-an-http-client-library-for-python-from-1-26-0-until-2) (high, CVSS 4, published 29 Sep 2026)
- [CVE-2024-37891: PYSEC-2026-1995 - urllib3's Proxy-Authorization request header isn't stripped during cross-origin redirects](https://junglewise.ai/threats/cve-2024-37891-urllib3-proxy-authorization-header-leak-in-cross-origin-redirects) (low, CVSS 3.1, published 7 Jul 2026)
- [CVE-2026-9375: urllib3 denial of service via Brotli decompression bomb bypass](https://junglewise.ai/threats/cve-2026-9375-urllib3-denial-of-service-via-brotli-decompression-bomb-bypass) (high, CVSS 7.5, published 19 Jun 2026)
- [CVE-2026-44432: urllib3 resource exhaustion via improper handling of compressed data](https://junglewise.ai/threats/cve-2026-44432-urllib3-resource-exhaustion-via-improper-handling-of-compressed) (high, CVSS 7.5, published 13 May 2026)
- [CVE-2026-44431: urllib3 sensitive header leak in ProxyManager low-level redirects](https://junglewise.ai/threats/cve-2026-44431-urllib3-sensitive-header-leak-in-proxymanager-low-level-redirects) (medium, CVSS 5.3, published 13 May 2026)
- [CVE-2025-66471: urllib3 streaming API improper compression handling](https://junglewise.ai/threats/cve-2025-66471-urllib3-streaming-api-improper-compression-handling) (high, CVSS 7.5, published 5 Dec 2025)
- [CVE-2021-33503: urllib3 ReDoS in URL authority parser](https://junglewise.ai/threats/cve-2021-33503-urllib3-redos-in-url-authority-parser) (high, CVSS 7.5, published 1 Jun 2021)

## Most severe Urllib3 vulnerabilities

- [CVE-2021-33503: urllib3 ReDoS in URL authority parser](https://junglewise.ai/threats/cve-2021-33503-urllib3-redos-in-url-authority-parser) (high, CVSS 7.5, published 1 Jun 2021)
- [CVE-2026-44432: urllib3 resource exhaustion via improper handling of compressed data](https://junglewise.ai/threats/cve-2026-44432-urllib3-resource-exhaustion-via-improper-handling-of-compressed) (high, CVSS 7.5, published 13 May 2026)
- [CVE-2025-66471: urllib3 streaming API improper compression handling](https://junglewise.ai/threats/cve-2025-66471-urllib3-streaming-api-improper-compression-handling) (high, CVSS 7.5, published 5 Dec 2025)
- [CVE-2026-9375: urllib3 denial of service via Brotli decompression bomb bypass](https://junglewise.ai/threats/cve-2026-9375-urllib3-denial-of-service-via-brotli-decompression-bomb-bypass) (high, CVSS 7.5, published 19 Jun 2026)
- [CVE-2026-97689: urllib3 HTTP client unbounded memory allocation in chunked transfer](https://junglewise.ai/threats/cve-2026-97689-urllib3-is-an-http-client-library-for-python-from-1-10-3-until-2) (high, CVSS 4, published 29 Sep 2026)
- [CVE-2026-97687: urllib3 HTTPS proxy TLS settings isolation](https://junglewise.ai/threats/cve-2026-97687-urllib3-is-an-http-client-library-for-python-from-1-26-0-until-2) (high, CVSS 4, published 29 Sep 2026)
- [CVE-2026-44431: urllib3 sensitive header leak in ProxyManager low-level redirects](https://junglewise.ai/threats/cve-2026-44431-urllib3-sensitive-header-leak-in-proxymanager-low-level-redirects) (medium, CVSS 5.3, published 13 May 2026)
- [CVE-2026-97688: urllib3 infinite loop in Deflate decoder](https://junglewise.ai/threats/cve-2026-97688-urllib3-is-an-http-client-library-for-python-from-2-6-2-until-2-8) (medium, CVSS 4, published 29 Sep 2026)
- [CVE-2024-37891: PYSEC-2026-1995 - urllib3's Proxy-Authorization request header isn't stripped during cross-origin redirects](https://junglewise.ai/threats/cve-2024-37891-urllib3-proxy-authorization-header-leak-in-cross-origin-redirects) (low, CVSS 3.1, published 7 Jul 2026)

## Vulnerabilities per week

Nothing in the last four weeks, down from 3 vulnerabilities in the four before.

| Week of | Vulns | Critical | Exploited |
| --- | --- | --- | --- |
| 17 Aug 2026 | 0 | 0 | 0 |
| 24 Aug 2026 | 0 | 0 | 0 |
| 31 Aug 2026 | 0 | 0 | 0 |
| 7 Sep 2026 | 0 | 0 | 0 |
| 14 Sep 2026 | 0 | 0 | 0 |
| 21 Sep 2026 | 0 | 0 | 0 |
| 28 Sep 2026 | 3 | 0 | 0 |
| 5 Oct 2026 | 0 | 0 | 0 |
| 12 Oct 2026 | 0 | 0 | 0 |
| 19 Oct 2026 | 0 | 0 | 0 |
| 26 Oct 2026 | 0 | 0 | 0 |
| 2 Nov 2026 | 0 | 0 | 0 |
| 9 Nov 2026 | 0 | 0 | 0 |

## Urllib3 technologies

- [Urllib3](https://junglewise.ai/threats/technologies/urllib3-urllib3): 5 vulnerabilities

## Sources

NVD, GitHub Security Advisories, OSV, the CISA Known Exploited Vulnerabilities catalog, FIRST EPSS and vendor advisories. Rebuilt every hour. Cite as: Junglewise Threat Intelligence, "Urllib3 vulnerabilities", https://junglewise.ai/threats/vendors/urllib3, 9 November 2026.