CVE-2026-7881 Concrete CMS CVE debrief

Who should care

Organizations running Concrete CMS sites that use Express forms, especially administrators, developers, and security teams responsible for form submission data and access controls.

Technical summary

The vulnerability is an IDOR in the Express Entry Detail block, exposed through the exEntryID parameter. According to the CVE description and NVD metadata, improper object-level authorization can allow unauthorized access to Express form submissions. NVD maps the issue to CWE-639 and records the vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N, indicating network-reachable impact with no privileges or user interaction required, but with limited confidentiality impact.

Defensive priority

Medium. The issue is publicly disclosed and affects a common CMS component that may expose submitted form data. Prioritize if your deployment uses Express forms or stores sensitive submission content.

Recommended defensive actions

• Upgrade Concrete CMS to a fixed version if available; confirm the remediation guidance in the official Concrete CMS release notes linked from NVD.
• Review any access-control checks around Express Entry Detail and verify that object-level authorization is enforced for each submission record.
• Audit whether sensitive data is stored in Express form submissions and restrict exposure accordingly.
• Monitor logs for unusual access patterns targeting the Express Entry Detail block or requests using exEntryID.
• If you cannot patch immediately, limit exposure of affected pages and minimize who can access Express submission views.

Evidence notes

This debrief is based only on the supplied CVE record and the official NVD reference to Concrete CMS release notes. The CVE description states the issue affects Concrete CMS 9.5.0 and below, involves an IDOR in the Express Entry Detail block via exEntryID, and can lead to unauthorized access to all Express form submissions. NVD records the weakness as CWE-639 and provides the CVSS v4.0 vector and score. Vendor attribution in the supplied corpus is low-confidence/needs-review, but the linked reference points to Concrete CMS documentation.

Official resources