CVE-2026-121458
Instatic before 0.0.21 Authorization Bypass via MCP Content Read Tools
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
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 Attackers can use the MCP interface to retrieve private or unpublished draft content and enumerate rows from the posts system table, resulting in cross-user data disclosure.
| CWE | CWE-862 |
| Vendor | corebunch |
| Product | instatic |
| Published | Nov 3, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
Affected Versions
CoreBunch / Instatic
0.0.12 < 0.0.21
References
Credits
Sriman Aluvala