Auth bypass in Fluentcms
CVE-2026-86271
A vulnerability was found in FluentCMS up to 0.0.5. This affects the function GetAccessible of the file src/Backend/FluentCMS.Services/Permissions/PermissionManager.cs. Performing a manipulation results in missing authorization. It is possible to initiate the attack remotely. The exploit has been made public and could be used. The project was informed of the problem early through an issue report but has not responded yet.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.7 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L.
EPSS exploit prediction
EPSS: 0.004 (32.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 33rd percentile — 32.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.002
Affected products
- Fluentcms — versions 0.0.1, 0.0.2, 0.0.3
Weakness classification (CWE)
References
- vuldb.com/vuln/399430 (technical-description, vdb-entry)
- vuldb.com/vuln/399430/cti (signature, permissions-required)
- vuldb.com/cve/CVE-2026-86271 (third-party-advisory)
- vuldb.com/submit/904824 (third-party-advisory)
- github.com/fluentcms/FluentCMS/issues/2409 (issue-tracking, exploit)
- github.com/fluentcms/FluentCMS/ (product)
Frequently asked questions
- What is CVE-2026-86271?
- CVE-2026-86271 is a medium-severity vulnerability in Fluentcms, classified under Missing Authorization. CVSS score: 4.7/10. Published 2026-09-07.
- How severe is CVE-2026-86271?
- Medium severity. CVSS v3 base score is 4.7 out of 10.