CVE-2021-39214High· 8.1▾ MidnightPoC availableLacking Protection against HTTP Request Smuggling in mitmproxy
▾ Midnight zone — Critical, or high with PoC / in-the-wild
impact 44.6 · likelihood 0.2 · exploitation 12
A public proof-of-concept already exists for this vulnerability — see Exploit availability below.
Public exploit / PoC code seen in 1 source. Availability, not in-the-wild use.
Exploit-prediction probability, daily snapshots since Aug 5.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via OSV
Last analysed / modified upstream
1.2%
1 GitHub repo
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 mitmproxy would only see one request, the target server would see multiple requests. A smuggled request is still captured as part of another request's body, but 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 you use mitmproxy to protect an HTTP/1 service, no action is required.
The vulnerability has been fixed in mitmproxy 7.0.3 and above.
We thank João Sobral (@chinchila) for responsibly disclosing this vulnerability to the mitmproxy team.
mitmproxy < 7.0.3Upgrade to a patched release:
mitmproxy 7.0.3Field changes observed since this record was first indexed.
Connected by shared product, vendor, weakness, or advisory.