CVE-2025-23217High▾ TwilightMitmweb API Authentication Bypass Using Proxy Server
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 41.3 · likelihood 0.2 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 8.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via OSV
0.8%
0.8% → 0.8%
Last analysed / modified upstream
In mitmweb 11.1.0 and below, a malicious client can use mitmweb's proxy server (bound to *:8080 by default) to access mitmweb's internal API (bound to 127.0.0.1:8081 by default). In other words, while the client cannot access the API directly (good), they can access the API through the proxy (bad). An attacker may be able to escalate this SSRF-style access to remote code execution.
The mitmproxy and mitmdump tools are unaffected. Only mitmweb is affected. The block_global option, which is enabled by default, blocks connections originating from publicly-routable IP addresses in the proxy. The attacker needs to be in the same local network.
The vulnerability has been fixed in mitmproxy 11.1.2 and above.
We thank Stefan Grönke (@gronke) for reporting this vulnerability as part of a security audit by Radically Open Security. This audit was supported by the NGI0 Entrust fund established by NLnet.
mitmproxy < 11.1.2Upgrade to a patched release:
mitmproxy 11.1.2Connected by shared product, vendor, weakness, or advisory.