# 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 request parameter.

Source: https://junglewise.ai/threats/cve-2019-11236-improper-neutralization-of-crlf-sequences-in-urllib3-library-for  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2019-04-15  
License: CC BY 4.0 with a link back

CVE-2019-11236 · Severity: low · CVSS 3 · Published 2019-04-15

In the urllib3 library through 1.24.1 for Python, CRLF injection is possible if the attacker controls the request parameter.

Technologies: [urllib3 (PyPI)](https://junglewise.ai/threats/technologies/urllib3). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2019-11236 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2019-11236 being exploited in the wild.

**How severe is CVE-2019-11236?** Low severity, with a CVSS score of 3, published 15 April 2019.

**Which products and versions are affected?** urllib3 (PyPI) ECOSYSTEM:introduced=0,fixed=1.24.3.

**Is there a fix for CVE-2019-11236?** Yes. urllib3 (PyPI): upgrade to 1.24.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2019-11236?** Check whether you run urllib3 (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- urllib3 (PyPI): upgrade to 1.24.3 or later

  ```sh
  pip install "urllib3>=1.24.3"
  ```


## Affected products

- urllib3 (PyPI) ECOSYSTEM:introduced=0,fixed=1.24.3

## Identifiers

- CVE-2019-11236
- GHSA-r64q-w8jr-g9qp
- PYSEC-2019-132

## Related threats

- [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)
- [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)
- [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)
- [PYSEC-2026-1997 - urllib3 does not control redirects in browsers and Node.js](https://junglewise.ai/threats/cve-2025-50182-urllib3-does-not-control-redirects-in-browsers-and-node-js)
- [PYSEC-2026-1999 - urllib3 redirects are not disabled when retries are disabled on PoolManager instantiation](https://junglewise.ai/threats/cve-2025-50181-urllib3-redirects-are-not-disabled-when-retries-are-disabled-on)