# mitmproxy binaries embed a vulnerable python-hyper/h2 dependency

Source: https://junglewise.ai/threats/mitmproxy-binaries-embed-a-vulnerable-python-hyper-h2-dependency-e14cde4e  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-08-25  
License: CC BY 4.0 with a link back

Severity: medium · CVSS 4 · Published 2025-08-25

mitmproxy binaries embed a vulnerable python-hyper/h2 dependency

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

## Quick answers

**Is This vulnerability exploited in the wild?** No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.

**How severe is This vulnerability?** Medium severity, with a CVSS score of 4, published 25 August 2025.

**Which products and versions are affected?** mitmproxy (PyPI) ECOSYSTEM:introduced=0,fixed=12.1.2.

**Is there a fix for This vulnerability?** Yes. mitmproxy (PyPI): upgrade to 12.1.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected?** Check whether you run mitmproxy (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

- mitmproxy (PyPI): upgrade to 12.1.2 or later

  ```sh
  pip install "mitmproxy>=12.1.2"
  ```


## Affected products

- mitmproxy (PyPI) ECOSYSTEM:introduced=0,fixed=12.1.2

## Related threats

- [PYSEC-2026-1630 - Mitmweb API Authentication Bypass Using Proxy Server](https://junglewise.ai/threats/cve-2025-23217-mitmweb-api-authentication-bypass-using-proxy-server)
- [mitmproxy LDAP injection in LDAP proxy authentication](https://junglewise.ai/threats/cve-2026-40606-mitmproxy-ldap-injection-in-ldap-proxy-authentication)
- [Insufficient Protection against HTTP Request Smuggling in mitmproxy](https://junglewise.ai/threats/cve-2022-24766-insufficient-protection-against-http-request-smuggling-in)
- [mitmproxy HTTP request smuggling](https://junglewise.ai/threats/cve-2021-39214-mitmproxy-http-request-smuggling)
- [PYSEC-2018-56 - mitmweb in mitmproxy v4.0.3 allows DNS Rebinding attacks, related to tools/web/app.py.](https://junglewise.ai/threats/cve-2018-14505-mitmweb-in-mitmproxy-allows-dns-rebinding-attacks)