What is CVE-2026-7886?

CVE-2026-7886 is a medium-severity vulnerability in Concrete Cms, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 4.3/10. Published 2026-05-21.

How severe is CVE-2026-7886?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Auth bypass in Concrete Cms

CVE-2026-7886

Concrete CMS 9.5.0 and below is vulnerable to IDOR in AddMessage/UpdateMessage via attachments[] parameter which can lead to file permission bypass. The `AddMessage` and `UpdateMessage` conversation controllers accept user-supplied file at…

Vulnerability class: IDOR (Insecure Direct Object Reference)

EPSS: 0.000 (4.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

Affected products

Concrete Cms — versions 5.0
Concretecms Concrete_cms

Weakness classification (CWE)

CWE-639 — Authorization Bypass Through User-Controlled Key

References

ff5b8ace-8b95-4078-9743-eac1ca5451de (release-notes, Release Notes)

Frequently asked questions

What is CVE-2026-7886?: CVE-2026-7886 is a medium-severity vulnerability in Concrete Cms, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 4.3/10. Published 2026-05-21.
How severe is CVE-2026-7886?: Medium severity. CVSS v3 base score is 4.3 out of 10.