CVE-2026-25904Public exploitNetwork attack vector

SSRF via sandbox access to host loopback

Published Feb 9, 2026 · Updated Feb 9, 2026

SSRF in Pydantic mcp-run-python 0.0.22 and earlier allows remote attackers to reach host-local services through sandboxed Python code. The Deno launch configuration grants Pyodide-executed code network access to localhost, allowing pyfetch to send requests through the host loopback interface. Exploitation requires an MCP client to execute attacker-influenced Python; reachable local services can be read or modified according to their own APIs.

CVSS severity5.8
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in Pydantic mcp-run-python 0.0.22 and earlier allows remote attackers to reach host-local services through sandboxed Python code. The Deno launch configuration grants Pyodide-executed code network access to localhost, allowing pyfetch to send requests through the host loopback interface. Exploitation requires an MCP client to execute attacker-influenced Python; reachable local services can be read or modified according to their own APIs.

The record

CVE
CVE-2026-25904
Published
Feb 9, 2026
Updated
Feb 9, 2026
Vendor
Pydantic
Product
mcp-run-python
Classifications
CWE-918, CAPEC-664, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Pydantic · mcp-run-pythonversion=0

Published CVSS scores

5.8JFrogCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
CAPEC-664Server Side Request Forgery
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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