CVE-2026-121458
Received Received - Intake

Instatic AI Content Read Tools Missing Authorization Vulnerability

Publication date: 2026-11-03

Last updated on: 2026-11-03

Assigner: VulnCheck

Description
Instatic before 0.0.21 contains a missing authorization vulnerability in its AI/MCP content read tools that allows low-privileged authenticated users with ai.chat and content.edit.own capabilities to access data rows belonging to other users by calling content_get_document and content_list_documents without the object-level authorization checks enforced by the normal HTTP API. Attackers can use the MCP interface to retrieve private or unpublished draft content and enumerate rows from the posts system table, resulting in cross-user data disclosure.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-11-03
Last Modified
2026-11-03
Generated
2026-11-03
AI Q&A
2026-11-03
EPSS Evaluated
N/A
NVD
CVE-2026-121458
EUVD
EUVD-2026-115812

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
CoreBunch Instatic 0.0.12

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-862 The product does not perform an authorization check when an actor attempts to access a resource or perform an action.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

This vulnerability is an authorization bypass in Instatic versions before 0.0.21. It allows low-privileged authenticated users with specific capabilities to access data belonging to other users through the AI/MCP content read tools. The functions content_get_document and content_list_documents lack proper authorization checks, enabling attackers to retrieve private or unpublished draft content and enumerate rows from the posts system table.

Detection Guidance

To detect this vulnerability, check if your Instatic instance is running a version before 0.0.21. Use commands like 'curl -s https://your-instatic-instance.com/version' or inspect package.json for version details. Monitor logs for unauthorized access attempts via MCP tools content_get_document or content_list_documents.

Impact Analysis

Attackers can exploit this to access unauthorized data, including private drafts and posts from other users. This leads to cross-user data disclosure, where sensitive information may be exposed. The impact includes potential loss of confidentiality for users' content and data.

Compliance Impact

This vulnerability could lead to non-compliance with data protection regulations like GDPR and HIPAA by enabling unauthorized access to personal or sensitive data. Organizations using affected versions may face legal penalties, reputational damage, and loss of trust due to data breaches.

Mitigation Strategies

Immediately upgrade Instatic to version 0.0.21 or later. Remove or restrict access for low-privileged users with ai.chat and content.edit.own capabilities until patched. Review logs for past unauthorized access and revoke any exposed MCP tokens.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-121458. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart

Security Radar

News mentioning this vulnerability
Loading related security news...