CVE-2021-39214

Description

mitmproxy is an interactive, SSL/TLS-capable intercepting proxy. In mitmproxy 7.0.2 and below, a malicious client or server is able to perform HTTP request smuggling attacks through mitmproxy. This means that a malicious client/server could smuggle a request/response through mitmproxy as part of another request/response's HTTP message body. While a smuggled request is still captured as part of another request's body, it does not appear in the request list and does not go through the usual mitmproxy event hooks, where users may have implemented custom access control checks or input sanitization. Unless one uses mitmproxy to protect an HTTP/1 service, no action is required. The vulnerability has been fixed in mitmproxy 7.0.3 and above.

How to fix CVE-2021-39214

To remediate CVE-2021-39214, upgrade the affected package to a fixed version below.

• —no fix listed
• —upgrade to 7.0.3 or later
• —upgrade to 7.0.3 or later

Is CVE-2021-39214 being exploited?

Low — EPSS is 0.2%, meaning exploitation activity has not been observed at scale.

Affected packages (3)

• from 0
• from 0, < 7.0.3
• from 0, < 7.0.3

CVSS scores

References (5)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2021-39214
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2021-39214
• PATCHgithub.com/mitmproxy/mitmproxy
• WEBgithub.com/mitmproxy/mitmproxy/security/advisories/GHSA-22gh-3r9q-xf38