What is CVE-2018-20405?

CVE-2018-20405 is a low-severity vulnerability in Bigtreecms Bigtree, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 2.7/10. Published 2018-12-23.

How severe is CVE-2018-20405?

Low severity. CVSS v3 base score is 2.7 out of 10.

Auth bypass in Bigtreecms Bigtree

CVE-2018-20405

BigTree 4.3 allows full path disclosure via authenticated admin/news/ input that triggers a syntax error. NOTE: This has been disputed with the following reasoning: "The issue reported requires full developer level access to the content management system where cross site scripting is not an issue -- you already have full control of the CMS including running arbitrary PHP.

Vulnerability class: IDOR (Insecure Direct Object Reference)

Published 2018-12-23 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 2.7 (Low). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.008 (55.6th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 56th percentile — 55.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000

Affected products

Bigtreecms Bigtree — versions 4.3

Weakness classification (CWE)

CWE-639 — Authorization Bypass Through User-Controlled Key

References

github.com/bigtreecms/BigTree-CMS/issues/354 (Exploit, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2018-20405?: CVE-2018-20405 is a low-severity vulnerability in Bigtreecms Bigtree, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 2.7/10. Published 2018-12-23.
How severe is CVE-2018-20405?: Low severity. CVSS v3 base score is 2.7 out of 10.