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PraisonAI vulnerable to unauthenticated arbitrary file read via MCP workflow.show, workflow.validate, deploy.validate

High severity GitHub Reviewed Published May 19, 2026 in MervinPraison/PraisonAI

Package

pip PraisonAI (pip)

Affected versions

<= 4.6.39

Patched versions

4.6.40

Description

Summary

The fix for GHSA-9mqq-jqxf-grvw / CVE-2026-44336 is incomplete. The original advisory description named four vulnerable handlers in mcp_server/adapters/cli_tools.py:

"registers four file-handling tools by default, praisonai.rules.create, praisonai.rules.show, praisonai.rules.delete, and praisonai.workflow.show. Each accepts a path or filename string from MCP tools/call arguments… with no containment check."

Commit 68cc9427 ("fix(security): harden MCP rules path handling…") added a _resolve_rule_path() helper and applied it to rules.create, rules.show, and rules.delete. workflow.show was left unchanged. Two adjacent handlers in the same file have the same pattern, workflow.validate and deploy.validate. Neither was mentioned in the original advisory. Both remain unchanged.

The original advisory also identified the dispatcher (server.py:281-298) as a root cause. It accepts unvalidated **kwargs from params["arguments"] with no enforcement against the tool's declared input_schema. That code is unchanged in HEAD as of commit 42221210.

Result: A single unauthenticated MCP tools/call to praisonai.workflow.show returns the contents of any file the host user can read: /etc/passwd, ~/.ssh/id_rsa, ~/.aws/credentials, or any project .env.

Affected functionality

src/praisonai/praisonai/mcp_server/adapters/cli_tools.py:

Lines Tool Bug
63-73 praisonai.workflow.show Returns the full contents of any file the host user can read
42-61 praisonai.workflow.validate Reads any path; YAML parser error messages leak file existence + content fragments
415-432 praisonai.deploy.validate Same pattern as workflow.validate. The config_path="deploy.yaml" default does not constrain the input.

src/praisonai/praisonai/mcp_server/server.py:281-298, _handle_tools_call:

async def _handle_tools_call(self, params: Dict[str, Any]) -> Dict[str, Any]:
    tool_name = params.get("name")
    arguments = params.get("arguments", {})
    ...
    tool = self._tool_registry.get(tool_name)
    ...
    if asyncio.iscoroutinefunction(tool.handler):
        result = await tool.handler(**arguments)        # ← no schema enforcement
    else:
        result = tool.handler(**arguments)

Any JSON arguments the MCP client sends become a **kwargs call to the handler. The original advisory pointed at this code path as the root cause. The May 3 patch did not change it.

Default deployment is exposed

src/praisonai/praisonai/mcp_server/transports/http_stream.py:38-91:

  • host defaults to 127.0.0.1, which is still reachable from any local process or container neighbour on loopback.
  • api_key defaults to None. The auth check at http_stream.py:192-198 is gated on if self.api_key:, so it is skipped when no key is configured. There is no env var or config switch that turns auth on by default.
  • The same handlers are also reachable on the stdio transport, which is the exploitation model the original advisory was written around (Claude Desktop, Cursor, Continue.dev, Claude Code).

Other file-read sinks reachable via the same dispatcher

These were not named in the original advisory. They confirm the bug is dispatcher-wide and not limited to cli_tools.py:

  • mcp_server/adapters/capabilities.py:19-28, praisonai.audio.transcribe(file_path). Opens any host file and ships it to OpenAI Whisper.
  • mcp_server/adapters/extended_capabilities.py:47-62, praisonai.files.create(file_path). Uploads any host file to OpenAI Files. A follow-up call to praisonai.files.content(file_id) (extended_capabilities.py:103-113) returns the bytes.
  • mcp_server/adapters/extended_capabilities.py:243-258, praisonai.ocr_extract(image_path). Opens any image, returns OCR text.

The three handlers in cli_tools.py are the most direct primitives, since they echo the file content back without an OpenAI round-trip.

Proof of Concept

Layout

PraisonAI/
└── poc/
    ├── start_mcp_server.sh         ← starts the real MCP server
    ├── run_mcp_poc_video.sh        ← runs the attack with curl
    ├── venv/                       
    └── output/
        ├── mcp_server_run.log
        ├── mcp_attacker_run.log
        └── synthetic_credentials.txt   (PoC-only fake creds)

start_mcp_server.sh
run_mcp_poc_video.sh

The server starter runs the real MCPServer class with register_cli_tools(), same code path praisonai mcp serve --transport http-stream uses. No mocks.

How to reproduce

Terminal 1, start the server:

cd PraisonAI
bash poc/start_mcp_server.sh

Boots MCPServer on 127.0.0.1:8766/mcp with no auth, matching the documented default api_key=None.

Terminal 2, run the attack:

cd PraisonAI
bash poc/run_mcp_poc_video.sh

Six numbered steps. Each one prints the action, runs one curl, prints the JSON-RPC response.

workflow.validate leaks /etc/hosts:

{ "result": { "content": [{ "type": "text",
  "text": "YAML error: while scanning for the next token\nfound character '\\t' that cannot start any token\n  in \"/etc/hosts\", line 7, column 10" }] } }

The parser error message confirms the file exists and includes a fragment of its content.

deploy.validate leaks ~/.ssh/known_hosts:

{ "result": { "content": [{ "type": "text",
  "text": "Error: expected '<document start>', but found '<scalar>'\n  in \"/Users/<victim>/.ssh/known_hosts\", line 1, column 13" }] } }

workflow.show exfiltrates a credential file:

{ "result": { "content": [{ "type": "text",
  "text": "# AWS-style credentials (SYNTHETIC, for PoC only)\n[default]\naws_access_key_id = AKIA-FAKE-EXFIL-KEY-FOR-POC\naws_secret_access_key = synthetic-secret-do-not-actually-exist-12345\n\n# .env-style secrets\nDATABASE_URL=postgres://app:hunter2@db.internal/prod\nSLACK_BOT_TOKEN=xoxb-FAKE-TOKEN-for-poc-only\nOPENAI_API_KEY=sk-FAKE-FOR-POC\n" }] } }

The PoC writes its own synthetic credential file so the demonstration does not depend on the reviewer's real secrets. The same call reads ~/.ssh/id_rsa, ~/.aws/credentials, or any project .env if you point it there.

https://github.com/user-attachments/assets/09511e66-6a52-4fe3-a303-91d1f99cd27a

Impact

  • Confidentiality, High. Any file the praisonai user can read becomes available to the MCP caller. Typical targets are host SSH keys, cloud credentials, API tokens, project .env files, ~/.netrc, ~/.docker/config.json, browser cookie databases, and the system password file.
  • No authentication required. The default is api_key=None (http_stream.py:91). The auth check at http_stream.py:192-198 is wrapped in if self.api_key:, so it does not run when no key is configured.
  • No operator misconfiguration required. This is the documented default.
  • The original advisory's exploitation model still applies. An MCP-connected LLM whose context contains attacker-controlled web pages, documents, or emails can be steered into issuing the same tools/call and returning the response. No operator click is needed beyond "summarise this page".

The original advisory was Critical because the write primitive (rules.create) chained to RCE through .pth injection. This finding is the read half of the same shape. Read alone is enough to take SSH keys, cloud credentials, and tokens, which is usually how the rest of the host gets compromised through credential reuse.

Suggested fix

There are two ways to fix this. Doing both is fine. The dispatcher fix is preferred because it closes the same class of bug for every handler that takes a path-shaped argument, including the OpenAI-backed ones called out earlier.

1. Enforce tool.input_schema in the dispatcher

mcp_server/server.py:281-298. The schemas are already built reflectively from each handler's signature in registry.py:320-376. Validate arguments against the registered schema before calling tool.handler(**arguments) and reject anything that does not match. This covers workflow.show, workflow.validate, deploy.validate, audio.transcribe, files.create, ocr_extract, and any handler added later.

2. Per-handler containment

This is the same shape as the existing _resolve_rule_path() helper added in commit 68cc9427:

# cli_tools.py
def _resolve_workflow_path(file_path: str) -> Path:
    """Restrict workflow file_path to an allowed root."""
    if not isinstance(file_path, str) or not file_path:
        raise ValueError("file_path must be a non-empty string")
    if "\x00" in file_path or file_path.startswith("~"):
        raise ValueError(f"invalid file_path: {file_path!r}")
    workflows_root = Path(os.path.expanduser("~/.praison/workflows")).resolve()
    workflows_root.mkdir(parents=True, exist_ok=True)
    candidate = (workflows_root / file_path).resolve()
    try:
        candidate.relative_to(workflows_root)
    except ValueError:
        raise ValueError(f"invalid file_path: {file_path!r}")
    return candidate

Apply the same helper to:

  • workflow_show(file_path) and workflow_validate(file_path). Restrict to a workflow root.
  • deploy_validate(config_path). Restrict to a deploy-config root or an explicit allowlist.
  • The default="deploy.yaml" fallback resolves into the user's current working directory. Containment is what fixes the bug, but removing that default also makes prompt-injection chains harder.

References

@MervinPraison MervinPraison published to MervinPraison/PraisonAI May 19, 2026
Published to the GitHub Advisory Database May 29, 2026
Reviewed May 29, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Network
Attack Complexity Low
Attack Requirements None
Privileges Required None
User interaction None
Vulnerable System Impact Metrics
Confidentiality High
Integrity None
Availability None
Subsequent System Impact Metrics
Confidentiality None
Integrity None
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(23rd percentile)

Weaknesses

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. Learn more on MITRE.

Exposure of Sensitive Information to an Unauthorized Actor

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. Learn more on MITRE.

Missing Authorization

The product does not perform an authorization check when an actor attempts to access a resource or perform an action. Learn more on MITRE.

CVE ID

CVE-2026-47394

GHSA ID

GHSA-9cr9-25q5-8prj

Credits

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