Vulnerability in Mitmproxy
CVE-2021-39214
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.
Vulnerability class: HTTP Request Smuggling
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.011 (63.1th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 63rd percentile — 63.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000
Affected products
- Mitmproxy — versions < 7.0.3
Weakness classification (CWE)
References
- github.com/mitmproxy/mitmproxy/security/advisories/GHSA-22gh-3r9q-xf38 (Third Party Advisory)
Frequently asked questions
- What is CVE-2021-39214?
- CVE-2021-39214 is a high-severity vulnerability in Mitmproxy, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 8.1/10. Published 2021-09-16.
- How severe is CVE-2021-39214?
- High severity. CVSS v3 base score is 8.1 out of 10.