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Fencer Intel
high 8.2

CVE-2025-23217 json

Mitmweb API Authentication Bypass Using Proxy Server

published last yr. modified last mo. also EUVD-2025-3147 , GHSA-wg33-5h85-7q5p , PYSEC-2026-1630

cvss
8.2
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 59%
public exploits
0
none known

Summary

mitmproxy is a interactive TLS-capable intercepting HTTP proxy for penetration testers and software developers and mitmweb is a web-based interface for mitmproxy. In mitmweb 11.1.1 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 cannot access the API directly, they can access the API through the proxy. 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. This vulnerability has been fixed in mitmproxy 11.1.2 and above. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Patch / fix

  • pypi mitmproxy 11.1.2
  • mitmproxy mitmproxy 11.1.2
  • mitmproxy Debian 14 8.1.1-4

debian advisories DEBIAN-CVE-2025-23217

  • python-mitmproxy openSUSE Tumbleweed 11.1.2-1.1

opensuse advisories openSUSE-SU-2025:14762-1

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CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
last yr.

Exploit prediction

0.87% chance of exploitation in the next 30 days, higher than 59% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
pypi mitmproxy
<11.1.2
11.1.2

Affected products

  • mitmproxy mitmproxy

Classification

Weakness
  • CWE-288 Authentication Bypass Using an Alternate Path or Channel
  • CWE-441 Unintended Proxy or Intermediary

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.