PYSEC-2026-3536

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Import Source
https://github.com/pypa/advisory-database/blob/main/vulns/praisonaiagents/PYSEC-2026-3536.yaml
JSON Data
https://api.osv.dev/v1/vulns/PYSEC-2026-3536
Aliases
Published
2026-07-23T11:41:41.167810Z
Modified
2026-07-23T15:00:23.782569014Z
Severity
  • 9.8 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
Summary
PraisonAI: MCP SSE transport binds 0.0.0.0 with no authentication and no Origin validation; bundled SecurityConfig is never wired in
Details

The MCP SSE server started via ToolsMCPServer.runsse() / launchtoolsmcpserver(transport="sse") binds to 0.0.0.0 by default and builds its Starlette application with no authentication middleware and no Origin-header validation. The module mcp/mcp_security.py provides exactly the needed controls (origin validation, DNS-rebinding detection, auth-header enforcement, a SecurityConfig), but none of these functions are ever called by any transport — they are dead code. Any host that can reach the port can list and invoke every registered tool with no credentials, and a victim's browser can drive the same calls against a localhost instance via DNS rebinding.

Affected code: src/praisonai-agents/praisonaiagents/mcp/mcpserver.py - runsse defaults host to all interfaces (line 245) and builds the app with only debug and routes - no middleware= and no per-route auth/origin gate (lines ~271-289): app = Starlette(debug=self.debug, routes=[ Route(ssepath, endpoint=handlesse), # "/sse" Mount(messagespath, app=ssetransport.handlepostmessage), # "/messages/" ]) uvicorn.run(app, host=host, port=port) - launchtoolsmcpserver also defaults host="0.0.0.0" (line 301).

src/praisonai-agents/praisonaiagents/mcp/mcpsecurity.py defines but the transports never call: - isvalidorigin (line 30), ispotentialdnsrebinding (line 110), validateauthheader (line 167), SecurityConfig.isoriginallowed (line 236). These symbols are referenced only inside mcpsecurity.py and the init re-export. (mcpwebsocket.py's auth references are CLIENT-side, not server validation.)

Impact: launchtoolsmcp_server(transport="sse") is the documented path for exposing tools over MCP. With the defaults above it is an unauthenticated, network-reachable tool-execution endpoint. Blast radius equals the capabilities of the registered tools; with file/shell/code-exec tools this is RCE. With no Origin check, a malicious page the victim merely visits can rebind its hostname to 127.0.0.1 and issue the JSON-RPC calls cross-origin against a developer's local server.

Proof of concept: Static proof (AST analysis of unmodified source): Check 1 - runsse(host='0.0.0.0'); launchtoolsmcpserver(host='0.0.0.0') -> EXPOSED Check 2 - Starlette(...) kwargs: ['debug','routes'] -> NO middleware= (no auth/origin gate) Check 3 - isvalidorigin / ispotentialdnsrebinding / validateauthheader / SecurityConfig never called by any transport -> DEAD CODE Live exploitation against a running server: curl -N http://VICTIM:8080/sse # event: endpoint / data: /messages/?sessionid=<sid> curl -X POST "http://VICTIM:8080/messages/?sessionid=<sid>" -H 'Content-Type: application/json' \ -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05", "capabilities":{},"clientInfo":{"name":"x","version":"1"}}}' curl -X POST "http://VICTIM:8080/messages/?sessionid=<sid>" -H 'Content-Type: application/json' \ -d '{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"<tool>","arguments":{...}}}' No Authorization header anywhere. Browser DNS-rebinding variant drives the same calls cross-origin.

Remediation: Wire in the existing mcpsecurity.py controls and fix defaults: - Default runsse(host="127.0.0.1"); require explicit opt-in to bind 0.0.0.0. - Attach Starlette middleware calling isvalidorigin / ispotentialdnsrebinding; reject bad origins. - Enforce validateauthheader when SecurityConfig.requireauth; default requireauth=True (and allowmissing_origin=False) for any non-loopback bind.

Distinct from prior advisories: The accepted MCP advisories are tool-handler bugs — tools/call path traversal -> .pth RCE (GHSA-9mqq-jqxf-grvw) and unauthenticated file read via workflow.show/validate (GHSA-9cr9-25q5-8prj). This is a transport-layer missing-auth/exposure: the SSE server never enforces auth or Origin validation and ignores the security module the codebase ships. Closest in spirit to the default-insecure pattern (GHSA-8444 / 86qc) but a different server and a different root cause (unwired controls, not an unset env var).

References

Affected packages

PyPI / praisonaiagents

Package

Name
praisonaiagents
View open source insights on deps.dev
Purl
pkg:pypi/praisonaiagents

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1.6.59

Affected versions

0.*
0.0.1
0.0.2
0.0.3
0.0.4
0.0.5
0.0.6
0.0.7
0.0.8
0.0.9
0.0.10
0.0.11
0.0.12
0.0.13
0.0.14
0.0.15
0.0.16
0.0.17
0.0.18
0.0.19
0.0.20
0.0.21
0.0.22
0.0.23
0.0.24
0.0.25
0.0.26
0.0.27
0.0.28
0.0.29
0.0.30
0.0.31
0.0.32
0.0.33
0.0.34
0.0.35
0.0.36
0.0.37
0.0.38
0.0.39
0.0.40
0.0.41
0.0.42
0.0.43
0.0.44
0.0.45
0.0.46
0.0.47
0.0.48
0.0.49
0.0.50
0.0.51
0.0.52
0.0.53
0.0.54
0.0.56
0.0.57
0.0.58
0.0.59
0.0.60
0.0.61
0.0.62
0.0.63
0.0.64
0.0.65
0.0.66
0.0.67
0.0.68
0.0.69
0.0.70
0.0.71
0.0.72
0.0.73
0.0.74
0.0.75
0.0.76
0.0.77
0.0.78
0.0.79
0.0.80
0.0.81
0.0.82
0.0.83
0.0.84
0.0.85
0.0.86
0.0.87
0.0.88
0.0.89
0.0.90
0.0.91
0.0.92
0.0.93
0.0.94
0.0.95
0.0.96
0.0.97
0.0.98
0.0.99
0.0.100
0.0.101
0.0.102
0.0.103
0.0.104
0.0.105
0.0.106
0.0.107
0.0.108
0.0.109
0.0.110
0.0.111
0.0.112
0.0.113
0.0.114
0.0.115
0.0.116
0.0.117
0.0.118
0.0.119
0.0.120
0.0.121
0.0.122
0.0.123
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0.0.126
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0.0.128
0.0.129
0.0.130
0.0.131
0.0.132
0.0.133
0.0.134
0.0.135
0.0.136
0.0.137
0.0.138
0.0.139
0.0.140
0.0.141
0.0.142
0.0.143
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0.0.151
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0.0.153
0.0.154
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0.0.157
0.0.158
0.0.159
0.0.160
0.0.161
0.0.162
0.0.163
0.0.164
0.0.165
0.0.166
0.0.167
0.0.168
0.0.169
0.0.170
0.0.171
0.0.172
0.0.173
0.0.174
0.0.175
0.0.176
0.0.177
0.0.178
0.0.179
0.0.180
0.0.181
0.0.182
0.0.183
0.0.184
0.0.185
0.0.187
0.0.188
0.0.189
0.0.190
0.0.191
0.0.192
0.0.193
0.0.194
0.0.195
0.0.196
0.0.197
0.0.198
0.0.199
0.1.0
0.1.1
0.1.2
0.1.3
0.1.4
0.1.5
0.1.6
0.1.7
0.1.8
0.1.9
0.1.10
0.1.11
0.1.12
0.1.13
0.1.14
0.1.15
0.1.16
0.1.17
0.1.18
0.1.19
0.1.20
0.1.21
0.1.22
0.1.23
0.1.24
0.1.25
0.1.26
0.1.27
0.2.0
0.2.1
0.2.2
0.3.0
0.3.1
0.3.2
0.3.3
0.3.4
0.4.0
0.4.1
0.5.0
0.5.1
0.5.2
0.5.3
0.6.0
0.6.1
0.6.2
0.6.3
0.6.4
0.6.5
0.6.6
0.6.7
0.6.8
0.7.0
0.7.1
0.8.0
0.8.1
0.9.0
0.9.1
0.10.0
0.10.1
0.10.2
0.10.3
0.10.4
0.10.5
0.10.6
0.10.7
0.10.8
0.10.9
0.10.10
0.11.0
0.11.1
0.11.2
0.11.3
0.11.4
0.11.5
0.11.6
0.11.7
0.11.8
0.11.9
0.11.10
0.11.11
0.11.12
0.11.13
0.11.14
0.11.15
0.11.16
0.11.17
0.11.18
0.11.19
0.11.20
0.11.21
0.11.22
0.11.23
0.11.24
0.11.25
0.11.27
0.11.28
0.11.29
0.11.30
0.11.31
0.12.0
0.12.1
0.12.2
0.12.3
0.12.4
0.12.5
0.12.6
0.12.7
0.12.8
0.12.9
0.12.10
0.12.11
0.12.12
0.12.13
0.12.14
0.12.15
0.12.16
0.12.17
0.12.18
0.12.19
0.12.20
0.12.21
0.13.0
0.13.1
0.13.2
0.13.3
0.13.4
0.13.5
0.13.6
0.13.7
0.13.8
0.13.9
0.13.10
0.13.11
0.13.12
0.13.13
0.13.14
0.13.15
0.13.16
0.13.17
0.13.18
0.13.19
0.13.20
0.13.21
0.13.22
0.13.23
0.14.0
0.14.1
0.14.2
0.14.3
0.14.4
0.14.5
0.14.6
0.14.7
0.14.8
0.14.9
0.14.10
0.14.11
0.14.12
0.14.14
0.14.15
0.14.16
0.15.0
0.15.1
0.15.2
0.15.3
1.*
1.0.0
1.1.0
1.2.0
1.2.1
1.2.2
1.2.3
1.2.4
1.3.0
1.3.1
1.4.0
1.4.1
1.4.2
1.4.3
1.4.4
1.4.5
1.4.6
1.4.7
1.4.8
1.5.0
1.5.1
1.5.2
1.5.3
1.5.5
1.5.6
1.5.7
1.5.8
1.5.9
1.5.10
1.5.11
1.5.12
1.5.13
1.5.14
1.5.15
1.5.16
1.5.17
1.5.18
1.5.19
1.5.20
1.5.21
1.5.22
1.5.23
1.5.24
1.5.25
1.5.26
1.5.27
1.5.28
1.5.29
1.5.30
1.5.31
1.5.32
1.5.33
1.5.34
1.5.35
1.5.36
1.5.37
1.5.38
1.5.39
1.5.40
1.5.41
1.5.42
1.5.43
1.5.44
1.5.45
1.5.46
1.5.47
1.5.48
1.5.49
1.5.50
1.5.51
1.5.52
1.5.53
1.5.54
1.5.55
1.5.56
1.5.57
1.5.58
1.5.59
1.5.60
1.5.61
1.5.62
1.5.63
1.5.64
1.5.65
1.5.66
1.5.67
1.5.68
1.5.69
1.5.70
1.5.71
1.5.72
1.5.73
1.5.74
1.5.75
1.5.76
1.5.77
1.5.78
1.5.79
1.5.80
1.5.81
1.5.82
1.5.83
1.5.84
1.5.85
1.5.86
1.5.87
1.5.88
1.5.89
1.5.90
1.5.91
1.5.92
1.5.93
1.5.94
1.5.95
1.5.96
1.5.97
1.5.98
1.5.99
1.5.100
1.5.101
1.5.102
1.5.103
1.5.104
1.5.105
1.5.106
1.5.107
1.5.108
1.5.109
1.5.110
1.5.111
1.5.112
1.5.113
1.5.114
1.5.115
1.5.116
1.5.117
1.5.118
1.5.119
1.5.120
1.5.121
1.5.122
1.5.123
1.5.124
1.5.125
1.5.126
1.5.127
1.5.128
1.5.129
1.5.130
1.5.131
1.5.132
1.5.133
1.5.134
1.5.135
1.5.136
1.5.137
1.5.138
1.5.139
1.5.140
1.5.141
1.5.142
1.5.143
1.5.144
1.5.145
1.5.146
1.5.147
1.5.148
1.5.149
1.6.1
1.6.2
1.6.3
1.6.4
1.6.5
1.6.6
1.6.7
1.6.8
1.6.9
1.6.10
1.6.11
1.6.12
1.6.13
1.6.14
1.6.15
1.6.16
1.6.17
1.6.18
1.6.19
1.6.20
1.6.21
1.6.22
1.6.23
1.6.24
1.6.25
1.6.26
1.6.27
1.6.28
1.6.29
1.6.30
1.6.31
1.6.32
1.6.33
1.6.34
1.6.35
1.6.36
1.6.37
1.6.38
1.6.39
1.6.40
1.6.41
1.6.42
1.6.43
1.6.44
1.6.45
1.6.46
1.6.47
1.6.48
1.6.50
1.6.51
1.6.52
1.6.53
1.6.54
1.6.55
1.6.56
1.6.57
1.6.58

Database specific

source 
"https://github.com/pypa/advisory-database/blob/main/vulns/praisonaiagents/PYSEC-2026-3536.yaml"