critical CVSS 10

CVE-2026-34938·Python vulnerability

PraisonAI is a multi-agent teams system. Prior to version 1.5.90, execute_code() in praisonai-agents runs attacker-controlled Python inside a three-layer sandbox that can be fully bypassed by passing a str subclass with an overridden startswith() method to the _safe_getattr wrapper, achieving arbitrary OS command execution on the host. This issue has been patched in version 1.5.90.

Severity
critical
Software
Python
Fixed in
1.5.90
Published
2026-04-03

Affected versions

Until: 1.5.90

Fixed in: 1.5.90

How to fix this CVE

Update PraisonAI to version 1.5.90 or later to patch a critical sandbox escape vulnerability in the execute_code() function. Organizations using PraisonAI agents should prioritize this update immediately, as the vulnerability allows attackers to bypass multi-layer sandbox protections and execute arbitrary operating system commands. Verify the patched version is deployed across all systems running PraisonAI before resuming agent-based code execution workloads.

sudo dnf update python3-praisonai || pip3 install --upgrade praisonai-agents>=1.5.90

Defensia detects this vulnerability

How to check if you are affected

  1. Check installed PraisonAI version: pip3 show praisonai-agents | grep Version
  2. Verify execute_code() function is in use: grep -r 'execute_code\|praisonai' /path/to/application --include='*.py' | head -20
  3. Search application logs for suspicious str subclass instantiations or startswith() method overrides: grep -i 'startswith\|subclass' /var/log/application.log | grep -v '^#'
  4. Confirm patch installation: pip3 show praisonai-agents | grep Version && python3 -c 'import praisonai_agents; print(praisonai_agents.__version__)' | grep -E '^1\.5\.(9[0-9]|[1-9][0-9]{2,})|^[2-9]'

FAQ

What is CVE-2026-34938?

CVE-2026-34938 is a critical sandbox escape vulnerability in PraisonAI's execute_code() function that allows attackers to bypass security protections by passing a malicious string subclass with an overridden startswith() method, leading to arbitrary OS command execution on the host system.

Is CVE-2026-34938 being actively exploited?

No, CVE-2026-34938 is not currently listed in CISA's Known Exploited Vulnerabilities (KEV) catalog and no public exploits are available. However, the critical CVSS 10.0 severity and ease of exploitation warrant immediate patching.

What versions of PraisonAI are affected by CVE-2026-34938?

All versions of PraisonAI prior to 1.5.90 are vulnerable. The praisonai-agents package versions before 1.5.90 contain the vulnerable execute_code() function.

How do I check if my server is vulnerable to CVE-2026-34938?

Run: pip3 show praisonai-agents | grep Version. If the version is below 1.5.90, your system is vulnerable. Additionally, check if PraisonAI is actively running code execution workloads: ps aux | grep -i praison

Does Defensia detect CVE-2026-34938?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If PraisonAI is installed on a monitored server, CVE-2026-34938 will appear in your dashboard with remediation steps and severity alerts.

Related Python CVEs

CVE-2026-28505CVSS 10Tautulli is a Python based monitoring and tracking tool for Plex Media Server. Prior to version 2.17.0, the str_eval() function in notification_handler.py implements a sandboxed eval() for notification text templates. The sandbox attempts to restrict callable names by inspecting code.co_names of the compiled code object. However, co_names only contains names from the outer code object. When a lambda expression is used, it creates a nested code object whose attribute accesses are stored in code.co_consts, NOT in code.co_names. The sandbox never inspects nested code objects. This issue has been patched in version 2.17.0.
CVE-2026-33054CVSS 10Mesop is a Python-based UI framework that allows users to build web applications. Versions 1.2.2 and below contain a Path Traversal vulnerability that allows any user supplying an untrusted state_token through the UI stream payload to arbitrarily target files on the disk under the standard file-based runtime backend. This can result in application denial of service (via crash loops when reading non-msgpack target files as configurations), or arbitrary file manipulation. This vulnerability heavily exposes systems hosted utilizing FileStateSessionBackend. Unauthorized malicious actors could interact with arbitrary payloads overwriting or explicitly removing underlying service resources natively outside the application bounds. This issue has been fixed in version 1.2.3.
CVE-2026-25632CVSS 10EPyT-Flow is a Python package designed for the easy generation of hydraulic and water quality scenario data of water distribution networks. Prior to 0.16.1, EPyT-Flow’s REST API parses attacker-controlled JSON request bodies using a custom deserializer (my_load_from_json) that supports a type field. When type is present, the deserializer dynamically imports an attacker-specified module/class and instantiates it with attacker-supplied arguments. This allows invoking dangerous classes such as subprocess.Popen, which can lead to OS command execution during JSON parsing. This also affects the loading of JSON files. This vulnerability is fixed in 0.16.1.
CVE-2026-26030CVSS 9.9Semantic Kernel, Microsoft's semantic kernel Python SDK, has a remote code execution vulnerability in versions prior to 1.39.4, specifically within the `InMemoryVectorStore` filter functionality. The problem has been fixed in version `python-1.39.4`. Users should upgrade this version or higher. As a workaround, avoid using `InMemoryVectorStore` for production scenarios.
CVE-2026-39888CVSS 9.9PraisonAI is a multi-agent teams system. Prior to 1.5.115, execute_code() in praisonaiagents.tools.python_tools defaults to sandbox_mode="sandbox", which runs user code in a subprocess wrapped with a restricted __builtins__ dict and an AST-based blocklist. The AST blocklist embedded inside the subprocess wrapper (blocked_attrs of python_tools.py) contains only 11 attribute names — a strict subset of the 30+ names blocked in the direct-execution path. The four attributes that form a frame-traversal chain out of the sandbox are all absent from the subprocess list (__traceback__, tb_frame, f_back, and f_builtins). Chaining these attributes through a caught exception exposes the real Python builtins dict of the subprocess wrapper frame, from which exec can be retrieved and called under a non-blocked variable name — bypassing every remaining security layer. This vulnerability is fixed in 1.5.115.

References

Track CVEs across your fleet automatically

Defensia scans your Linux servers and tells you exactly which ones are running vulnerable versions — including CVE-2026-34938. Free for 1 server.

Get started free