CVE-2026-33587Public exploitNetwork attack vector

Authenticated code execution via unsandboxed Jinja2 transformations

Published May 7, 2026 · Updated May 7, 2026

Server-side template injection in Open Notebook 1.8.3 and earlier allows remote authenticated users to execute code in its Docker container. The transformation prompt path passes user-authored templates to an unsandboxed Jinja2 Environment in the ai-prompter library, which evaluates template expressions as Python code. An application account with transformation-creation access is required; successful exploitation exposes environment variables and permits arbitrary file access and system commands inside the container.

CVSS severity9.2
Critical
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Server-side template injection in Open Notebook 1.8.3 and earlier allows remote authenticated users to execute code in its Docker container. The transformation prompt path passes user-authored templates to an unsandboxed Jinja2 Environment in the ai-prompter library, which evaluates template expressions as Python code. An application account with transformation-creation access is required; successful exploitation exposes environment variables and permits arbitrary file access and system commands inside the container.

The record

CVE
CVE-2026-33587
Published
May 7, 2026
Updated
May 7, 2026
Vendor
Open Notebook
Product
Open Notebook
Classifications
CWE-20, CWE-1336, CAPEC-545, CAPEC-242, T1059.006
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 7, 2026CVE publishedPublication date reported by the CVE source.
  2. May 7, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=1.8.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Open Notebook · Open Notebookversion=0 <=1.8.3

Published CVSS scores

10.0NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
9.9GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
9.2ENISACVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-1336Improper Neutralization of Special Elements Used in a Template Engine
CAPEC-545Pull Data from System Resources
CAPEC-242Code Injection
T1059.006Command and Scripting Interpreter: Python

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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