CVE-2026-40156 PraisonAI Affected by Implicit Execution of Arbitrary Code via Automatic `tools.py` Loading
Attackers can execute arbitrary code by placing a malicious tools.py file in the working directory, affecting users running PraisonAI.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-40156?
CVE-2026-40156 is a high-severity code injection vulnerability in MervinPraison PraisonAI, published on 10 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
PraisonAI is a multi-agent teams system. Prior to 4.5.128, PraisonAI automatically loads a file named tools.py from the current working directory to discover and register custom agent tools. This loading process uses importlib.util.spec_from_file_location and immediately executes module-level code via spec.loader.exec_module() without explicit user consent, validation, or sandboxing. The tools.py file is loaded implicitly, even when it is not referenced in configuration files or explicitly requested by the user. As a result, merely placing a file named tools.py in the working directory is sufficient to trigger code execution. This behavior violates the expected security boundary between user-controlled project files (e.g., YAML configurations) and executable code, as untrusted content in the working directory is treated as trusted and executed automatically. If an attacker can place a malicious tools.py file into a directory where a user or automated system (e.g., CI/CD pipeline) runs praisonai, arbitrary code execution occurs immediately upon startup, before any agent logic begins. This vulnerability is fixed in 4.5.128.
Which versions are affected by CVE-2026-40156?
3 open source packages ship an affected version, including praisonai. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
praisonai PyPI | All versions | 4.5.128 |
praisonai PyPI | All versions | 4.5.128 |
praisonai PyPI | All versions | 4.5.128 |
Products include Praison Praisonai.
How do I fix CVE-2026-40156?
Upgrade praisonai to 4.5.128 or later.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-40156 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40156 exists.
Other vulnerabilities in MervinPraison PraisonAI
- CVE-2026-39888 PraisonAIAgents has a sandbox escape via exception frame traversal in `execute_code` (subprocess mode)
- CVE-2026-41497 Incomplete fix for CVE-2026-34935: Command Injection in MervinPraison/PraisonAI
- CVE-2026-40288 PraisonAI: Critical RCE via `type: job` workflow YAML
- CVE-2026-39890 PraisonAI Affected by Remote Code Execution via YAML Deserialization in Agent Definition Loading
- CVE-2026-34934 PraisonAI: Second-Order SQL Injection in `get_all_user_threads`
Sources
Also known as GHSA-2g3w-cpc4-chr4, PYSEC-2026-2895.