CVE-2026-39888 PraisonAIAgents has a sandbox escape via exception frame traversal in `execute_code` (subprocess mode)
Attackers can escape the sandbox and execute arbitrary code by traversing exception frames to access restricted builtins in PraisonAIAgents.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-39888?
CVE-2026-39888 is a critical code injection vulnerability in MervinPraison praisonaiagents, published on 8 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
PraisonAI 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.
Which versions are affected by CVE-2026-39888?
3 open source packages ship an affected version, including praisonaiagents. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
praisonaiagents PyPI | All versions | 1.5.115 |
praisonaiagents PyPI | All versions | 1.5.115 |
praisonaiagents PyPI | All versions | 1.5.115 |
Products include Praison Praisonai.
How do I fix CVE-2026-39888?
Upgrade praisonaiagents to 1.5.115 or later.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-39888 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-39888 exists.
Other vulnerabilities in MervinPraison praisonaiagents
- 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`
- CVE-2026-34935 PraisonAI: OS Command Injection in MCPHandler.parse_mcp_command()
Sources
Also known as GHSA-qf73-2hrx-xprp, PYSEC-2026-486.