CyberSecBulletin
CVE-2026-39888NVD status: Analyzed

praisonaiagents: Violation of Secure Design Principles

CVE-2026-39888 is a critical-severity violation of secure design principles vulnerability in praisonaiagents from MervinPraison, with a CVSS 3.1 base score of 9.9 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected praisonaiagents versions: < 1.5.115. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.5% chance of exploitation within 30 days, which is low compared with other CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update Praisonai to 1.5.115 or a later version.
  2. Read the advisory on github.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
MervinPraisonpraisonaiagents< 1.5.115Not stated
PraisonPraisonaibefore 1.5.1151.5.115

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
ChangedThe attack can reach beyond the vulnerable component into other systems.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.19.9CriticalCNA (github.com)
CVSS 3.19.9CriticalNVD

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Violation of Secure Design Principles

The product violates well-established principles for secure design.

More Violation of Secure Design Principles vulnerabilities (CWE-657)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in praisonaiagents

All praisonaiagents vulnerabilities

Recent Violation of Secure Design Principles vulnerabilities

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