{"id":"CVE-2026-121458","title":"Instatic before 0.0.21 Authorization Bypass via MCP Content Read Tools","summary":"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 u…","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","cvssSource":"cna","cwe":["CWE-862"],"vendor":"CoreBunch","product":"Instatic","affected":["Instatic >= 0.0.12 < 0.0.21"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-03T17:23:06.950734Z"},"published":"2026-11-03","updated":"2026-11-03","sourceUpdated":"2026-11-03T18:31:26.636Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-121458","references":[{"url":"https://github.com/CoreBunch/Instatic/security/advisories/GHSA-x5cc-8486-8qqx","label":"Vendor Advisory"},{"url":"https://github.com/CoreBunch/Instatic/releases/tag/v0.0.21","label":"Vendor Patch"},{"url":"https://www.vulncheck.com/advisories/instatic-before-authorization-bypass-via-mcp-content-read-tools","label":"VulnCheck Advisory: Instatic before 0.0.21 Authorization Bypass via MCP Content Read Tools"}],"tags":["cve.org"],"epss":0.00309,"epssPercentile":0.23856,"ingestedAt":"2026-11-05T20:33:06.360Z","slug":"CVE-2026-121458","body":"## Overview\n\nInstatic 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 Attackers can use the MCP interface to retrieve private or unpublished draft content and enumerate rows from the posts system table, resulting in cross-user data disclosure.\n\n## Affected\n\n- `Instatic >= 0.0.12 < 0.0.21`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}