PraisonAIAgents has a sandbox escape via exception frame traversal in `execute_code` (subprocess mode)

published 2026-04-08 7 mo ago modified 2026-07-24 3 mo ago also GHSA-qf73-2hrx-xprp , PYSEC-2026-486 , EUVD-2026-20635

cvss: 10.0; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits: 0; none known

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.

Patch / fix

fixed in 2

pypi praisonaiagents 1.5.115
praison praisonai 1.5.115

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: total
Assessed: 7 mo ago (2026-04-09)

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	10.0	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
NVD	3.1	9.9	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
GitHub	3.1	9.9	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
OSV	3.1	9.9	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected packages

ecosystem	package	affected	fixed in
pypi	praisonaiagents	<1.5.115	1.5.115

Affected products

MervinPraison praisonaiagents

Classification

Weakness

CWE-657 Violation of Secure Design Principles
CWE-693 Protection Mechanism Failure

References

github.com /MervinPraison/PraisonAI/security/advisories/GHSA-qf73-2hrx-xprp
web, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2026-39888
advisory
github.com /MervinPraison/PraisonAI
package
pypi.org /project/praisonaiagents
package
github.com /advisories/GHSA-qf73-2hrx-xprp
advisory

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary