CVE-2026-57123 is a critical-severity (CVSS 9.8) Missing Authentication vulnerability in praisonaiagents. A fix is available for praisonaiagents — see the affected versions and patch details below.
PraisonAI: MCP SSE transport binds 0.0.0.0 with no authentication and no Origin validation; bundled SecurityConfig is never wired in
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-2026-57123.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-57123 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 394,803 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
praisonaiagentsReal-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
The MCP SSE server started via ToolsMCPServer.run_sse() / launch_tools_mcp_server(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/mcp_server.py
- run_sse defaults host to all interfaces (line 245) and builds the app with only
debugandroutes- no
middleware=and no per-route auth/origin gate (lines ~271-289): app = Starlette(debug=self._debug, routes=[ Route(sse_path, endpoint=handle_sse), # "/sse" Mount(messages_path, app=sse_transport.handle_post_message), # "/messages/" ]) uvicorn.run(app, host=host, port=port)
- no
- launch_tools_mcp_server also defaults host="0.0.0.0" (line 301).
src/praisonai-agents/praisonaiagents/mcp/mcp_security.py defines but the transports never call:
- is_valid_origin (line 30), is_potential_dns_rebinding (line 110), validate_auth_header (line 167), SecurityConfig.is_origin_allowed (line 236). These symbols are referenced only inside mcp_security.py and the init re-export. (mcp_websocket.py's auth references are CLIENT-side, not server validation.)
Impact: launch_tools_mcp_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 - run_sse(host='0.0.0.0'); launch_tools_mcp_server(host='0.0.0.0') -> EXPOSED Check 2 - Starlette(...) kwargs: ['debug','routes'] -> NO middleware= (no auth/origin gate) Check 3 - is_valid_origin / is_potential_dns_rebinding / validate_auth_header / SecurityConfig never called by any transport -> DEAD CODE Live exploitation against a running server: curl -N http://VICTIM:8080/sse
event: endpoint / data: /messages/?session_id=<sid>
curl -X POST "http://VICTIM:8080/messages/?session_id=<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/?session_id=<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 mcp_security.py controls and fix defaults:
- Default run_sse(host="127.0.0.1"); require explicit opt-in to bind 0.0.0.0.
- Attach Starlette middleware calling is_valid_origin / is_potential_dns_rebinding; reject bad origins.
- Enforce validate_auth_header when SecurityConfig.require_auth; default require_auth=True (and allow_missing_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).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | praisonaiagents | all versions | 1.6.59pip install --upgrade 'praisonaiagents==1.6.59' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for praisonaiagents, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update praisonaiagents to 1.6.59 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-57123 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.
Frequently Asked Questions
Is CVE-2026-57123 in your dependencies?
Find it across PyPI, including transitive dependencies.