Quick answers
- Is CVE-2026-18120 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-18120 being exploited in the wild.
- How severe is CVE-2026-18120?
- Medium severity, with a CVSS score of 5.9, published 16 September 2026.
- Which products and versions are affected?
- Concrete CMS before 9.5.3.
- Is there a fix for CVE-2026-18120?
- A patch was published on 2026-09-16: Fixed in version 9.5.3 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-18120 attacked?
- It is attacked over the network, in a web application.
- Am I affected by CVE-2026-18120?
- Check whether you run Concrete CMS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability is an authorization bypass in a legacy Express entry search endpoint that fails to invoke the canViewExpressEntries() permission check. An unauthenticated attacker with knowledge of an Express entity identifier can make network requests to this endpoint to retrieve entry search results in JSON format, bypassing the normal permission validation applied by the dashboard and CSV export flows. For Express entities that do not support entry-specific permissions (supportsEntrySpecificPermissions() returns false), the EntryList::ignorePermissions() method further disables per-entry permission filtering. The endpoint is network-accessible and requires no authentication or user interaction, allowing remote enumeration of sensitive data.
Affected products
- Concrete CMS Concrete CMS before 9.5.3
Timeline
- 2026-09-16: disclosed
- 2026-09-16: patched: Fixed in version 9.5.3