Inconsistent interpretation of HTTP requests in mitmproxy - CVE-2025-57804
Published: August 25, 2025
Vulnerability identifier: #VU114414
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2025-57804
CWE-ID: CWE-444
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: mitmproxy.org
Affected software:
mitmproxy
mitmproxy
Detailed vulnerability description
The vulnerability allows a remote attacker to perform HTTP request smuggling attacks.
The vulnerability exists due to improper validation of HTTP/2 requests in the embed python-hyper/h2 component when mitmproxy is in a configuration where it translates HTTP/2 to HTTP/1. A remote attacker can send a specially crafted HTTP request to the server and smuggle arbitrary HTTP headers.
Successful exploitation of vulnerability may allow an attacker to poison HTTP cache and perform phishing attacks.
How to mitigate CVE-2025-57804
Install updates from vendor's website.