How severe is CVE-2025-23217?

No CVSS score has been assigned to CVE-2025-23217 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2025-23217?

CVE-2025-23217 affects the following packages: mitmproxy (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2025-23217?

Update mitmproxy to 11.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-23217 is resolved across your whole dependency graph.

How do I detect CVE-2025-23217 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mitmproxy, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-23217 if there is no patch (or I can't update yet)?

Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Is CVE-2025-23217 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-23217 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-23217?

CVE-2025-23217 has an EPSS (Exploit Prediction Scoring System) score of 0.9%, placing it in the 59th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2025-23217?

CVE-2025-23217 is classified as CWE-288 (CWE-288), CWE-441 (CWE-441). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2025-23217 published, and has it been updated?

CVE-2025-23217 was published on February 6, 2025 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2025-23217 — mitmproxy

Fix: mitmproxy/mitmproxy@fa89055

CVE-2025-23217 is a CWE-288 vulnerability in mitmproxy. A fix is available for mitmproxy — see the affected versions and patch details below.

Mitmweb API Authentication Bypass Using Proxy Server

Also known asGHSA-wg33-5h85-7q5pPYSEC-2026-1630

Published

Feb 6, 2025

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-23217.

EPSS Exploitation Probability

via FIRST.org ↗

0.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs59th percentile — riskier than 59% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐍mitmproxy

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Impact

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.

Patches

The vulnerability has been fixed in mitmproxy 11.1.2 and above.

Acknowledgements

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.

Timeline

2025-01-14: Received initial report.
2025-01-14: Verified report and confirmed receipt.
2025-01-19: Shared patch with researcher.
2025-02-04: Received final confirmation that patch is working.
2025-02-05: Published patched release and advisory.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`mitmproxy`	all versions	11.1.2`pip install --upgrade 'mitmproxy==11.1.2'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mitmproxy, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update mitmproxy to 11.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-23217 is resolved across your whole dependency graph.
Workarounds
Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Frequently Asked Questions

### Impact 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](https://en.wikipedia.org/wiki/Server-side_request_forgery)-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

O3 Security · Impact-Aware SCA

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