CVE-2026-18121
NVD: Concrete CMS 9.5.2 and below is vulnerable to an authorization bypass (IDOR) because the frontend calendar lightbox endpoint (/ccm/calendar/view_event/{bID}/{occurrence_id}) does not verify that the caller is permitted to view the calendar that owns the... NVD: The controller loads the occurrence directly from an attacker‑supplied, sequential identifier without confirming that it belongs to the calendar configured on the referenced block. NVD: An unauthenticated visitor who can render any public calendar block with lightbox properties enabled could therefore supply an arbitrary occurrence identifier and disclose event metadata — title, date, description, page link, and configured event attributes —...
6.3 Severity
MEDIUM EPSS
0.0029 (22) KEV
-
Source-published summary
NVD: Concrete CMS 9.5.2 and below is vulnerable to an authorization bypass (IDOR) because the frontend calendar lightbox endpoint (/ccm/calendar/view_event/{bID}/{occurrence_id}) does not verify that the caller is permitted to view the calendar that owns the... NVD: The controller loads the occurrence directly from an attacker‑supplied, sequential identifier without confirming that it belongs to the calendar configured on the referenced block. NVD: An unauthenticated visitor who can render any public calendar block with lightbox properties enabled could therefore supply an arbitrary occurrence identifier and disclose event metadata — title, date, description, page link, and configured event attributes —...
Possible impact
This medium severity issue needs human triage to confirm exposure, affected versions, and vendor guidance for defensive exposure review.
Affected context
Affected product or version requires source confirmation.
Remediation / advisory
Remediation reference present; patch status requires confirmation in the linked advisory.
Why it matters
This medium severity issue needs human triage to confirm exposure, affected versions, and vendor guidance for defensive exposure review.; CVSS 6.3 (MEDIUM); EPSS percentile 22; not listed in KEV; Remediation reference present; patch status requires confirmation in the linked advisory; sources: NVD, OSV.
What to verify
Confirm affected product/version, vendor advisory, patch or mitigation, and exposure.
Exposure hint
exposure unknown
Impact tags
Urgency reasons
Source-derived note
Summary derived from NVD / OSV description; unsafe procedural detail is not shown.
Redaction metadata
- source summary used
- True
- fallback summary used
- False
- unsafe procedural detail present
- false
- raw source displayed
- false
- public summary redacted
- true
Remediation handoff
Public-safe static handoff for human/Codex remediation planning. Scan, patch, external execution, and auto remediation are disabled.
Safety note
This radar shows source-published defensive context only. Exploit procedures, exploit strings, scanner commands, and auto-remediation are not provided.