CVSS 4.0
7.1 highCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:NCVE-2026-121458
High (7.1). EPSS 0.3% estimated probability of exploitation activity in the next 30 days.
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 Attackers can use the MCP interface to retrieve private or unpublished draft content and enumerate rows from the posts system table, resulting in cross-user data disclosure.
Severity
CVSS 3.1
6.5 mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N- EPSS
- 0.3% estimated probability of exploitation activity in the next 30 days; 24th percentile. Scored 2026-11-04. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: none · Automatable: no · Technical impact: partial, assessed 2026-11-03. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- CWE
- CWE-862 Missing Authorization
- OWASP Top 10
- A01:2025 Broken Access Control
- Published
- Modified
- Record from
- the NVD, synced
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Explain CVE-2026-121458 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-121458?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-121458?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-121458 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| CoreBunch Instatic | from 0.0.12 before 0.0.21 |
Attack patterns (CAPEC)
- CAPEC-665 Exploitation of Thunderbolt Protection Flaws Likelihood: Low · Severity: Very High
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.